Disclaimer: If I owned Marvel or the X-Men there would be a lot fewer scantily clad women and a lot more plot lines that made sense. Needless to say, I don't own anything.
Reasons
They didn't get it.
They didn't, couldn't understand what it was like being him. Yes they had powers they didn't understand or couldn't control and it scared them, but they blended in. They looked normal. Before the recent event of their exposure they'd never had a problem walking down the street or fitting in, they looked human. He on the other hand wasn't so lucky.
His ever present uniform under the guise image inducer wasn't merely due to paranoia of being attacked as some of his friends suspected. He didn't wear it because it was one of the few articles of clothing that actually fit his awkward frame comfortably as others speculated either. The real reason was far more lurid than any of the students could imagine - he was covered in scars. His fur covered most of them but in the right conditions, if someone looked closely enough...
For fifteen years Kurt's demonic appearance brought terror and hate to all those who saw his true form. Intensified by the deep rooted Catholicism of his homeland, people sought to destroy him.
He and his foster family - his wonderful, loving, God-sent family - had been subjected to the worst that humanity had to offer. From shunning to hate, they'd endured vandalism, verbal slurs, physical attacks and even the cliche angry mob or two with pitchforks and torches.
He was quick and resourceful - he always had been - but hate was a strong motivator and he'd been captured by enraged perusers many more times than he was willing to admit. They were cruel and merciless, ironically more demonic than he was in their quest for 'purification'.
They'd tied him up in front of angry crowds to burn him at the stake or behead him. Angered onlookers would curse and spit on him while throwing stones or rotten fruit, screaming insults and promises of hell to him. He was barely able to escape those situations and not without serious injury. If he was lucky, an abnormally empathetic soul would help free him, or his family would intervene, but the hate never stopped. He was inevitably be captured again, sometimes by people with even worse intentions.
Unlike the village mobs mostly orchestrated by the church, the Hunters -a term he'd mentally dubbed them for lack of any other name- weren't a specific group or organization. They were random individuals, sometimes banding together, with only one desire - torture him for their own amusement. They didn't want to kill him, they possibly didn't even hate him, they were out for blood to feed their primal instincts and he was the perfect target for their deranged 'games'.
They'd come for him in the dark, isolating him before beginning their chase in territories unfamiliar to him. They'd wait for him to become exhausted from running and send the hounds - the horrible, blood-thirsty, wolf-like hounds - to corner him. Converging in in him the Hunters tied him up, or if they were in a good mood beat him sadistically into unconsciousness before dragging him of to their lair. That was where the real hell began.
He'd wake up striped naked in shackles and chains, sometimes squeezed into cages far to small, or bound by torture devices so horrible and gruesome they'd not been seen since the days of the crusades. The Hunters laughed and howled, asking him questions they didn't expect him to answer while they got drunk. They loved verbally abusing their catch before they were inebriated enough to fulfill their carnal desires.
Whipping had always been popular as well as good old fashioned beatings with anything from bare hands to spiked clubs. Sometimes they'd stab him with hot pokers or knives, or simply slash him up with blades, letting him bleed as they agitated his wounds with mild poisons or wrapped them in barbed-wire. Setting him on fire then almost drowning him was a common technique they implemented, as was caging him in with a rabid, half-starved wild animal to fight. Regrettably those were the mild 'games'. Most of the pain he endured was infinitely more creative and perverse.
To stay alive he'd learned not to scream. The more he screamed or cried, the more twisted the 'games' became. Like leaches they clung to him feeding on blood and terror, his only chance of escape was to go catatonic and let them do as they pleased to his body and pray they lost interest. For whatever reason the Hunters never killed him. When they finally got bored with him they'd leave his broken and molested form to rot wherever they decided to dump him
Delirious with pain he'd always somehow managed to crawl home, though he couldn't remember how he'd done it most of the time. He'd wake up in his bed, body screaming in pain with his worried family huddled around him in worry, desperately fighting to keep him alive. He could never figure out why they did it - how they could put up with the hate forced upon them because of him - how they could possibly love him, but they did and the feeling was unendingly reciprocated.
When his parents had first been contacted by the Institute they'd been afraid to give him up. They were afraid of what might happen to him, that the seeming paradise Professor Xavier offered was another lie to hurt their son. In the end it had been Kurt who'd forced them to let him go, he'd told them it was for the best and he trusted the man.
The real reason was his hope that with him gone his family could have a normal, peaceful life even if he was damning himself by going to America. He just wanted them to be happy.
Of course, the Institute was everything the Professor had promised. When he was given the image inducer it was the best moment of his life - he could finally be seen as a person and not a demon!
Xavier had become Kurt's saviour. He'd given the tormented boy hope and a new life if only for a short time, and that meant more to him than anything. For the first time in his life Kurt was happy.
At the Institute he had gained respect, acceptance, a loving pseudo-family, and as normal a life as he could ever hope to achieve. The attacks of other mutants, exhausting training sessions, and even the deadly situations he occasionally found himself in were nothing compared to his old life. He was in heaven.
Emphasis on was.
Bolivar Trask and his damned Sentinel project ruined it all. If Kurt had the heart to hurt someone that man would have been dead long ago, not locked up in some S.H.I.E.L.D. facility somewhere rotting. Ever since the exposure of mutants to the general public his friends were pariahs, met with fear and hate wherever they went, a situation entirely too familiar to him.
Luckily his image inducer had saved him from exposure, keeping his identity a secret. He was so thankful, so relieved to know he was still considered normal that it made his heart ace with guilt. His friends were out there being harassed while he remained blissfully innominate. Not that they'd let him forget it.
No one said anything outright but he saw the disappointed looks and scathing glances sent in his direction. They didn't avoid him but they were cold and impartial, often ignoring him completely. It hurt and he hated himself for betraying them, but they didn't understand, they couldn't.
His entire life was a mirror of hid friends' current problems amplified by a million. They were hated and mocked, even attacked, but it was nothing they couldn't handle. They knew how to fight, they had friends to support them and a home to escape from the harsh reality of the world. Kurt had never had such luxuries in Germany, he was alone and abused, his family hiding in fear because of him.
Over the years he'd learned more about torture than even the most experienced interrogators through first hand experience. Disturbingly, he'd intentionally repressed the worst of his memories while still retaining a vast array of knowledge on the subject...
Unlike he had been, his friends weren't afraid to go out - they didn't fear capture and they weren't hunted after the first incident. Most of their anger came from resentment of the world's intolerance. It was an understandable reaction, but it didn't warrant the vehemence they gave it. They didn't know true hell now and they never had. Comfy and cozy in their mansions or houses, even an orphanage was heaven in his eyes. Try as he might, he couldn't help being spiteful.
For the first time he was seen as normal and they wanted to take it away from him. It wasn't fair! Why would they want to make him deal with the same problems they had? Weren't they his friends? Shouldn't they want him to be happy? How dare they shun him for wanting to stay hidden!
It wasn't as if he wouldn't help them out when they needed it, but that didn't mean he had to reveal himself to do so. Not that he wouldn't if it was absolutely necessary, but he wanted his decade or so of peace, after all they'd all gotten theirs. Why couldn't his friends understand that?
Even Dr. McCoy and Storm were giving him disapproving looks. Hell! Amanda was pressing him to ditch the image inducer and he couldn't understand why. Only the Professor seemed to accept his actions for what they were, but the man knew everything about him so he didn't count. Logan hadn't mentioned anything one way or the other for whatever reason, but he wasn't acting any different around Kurt like the others, and the boy was immensely thankful for it.
He had told him his secret wouldn't last for long but Logan hadn't said it to be cruel, he was just being his logically pessimistic self. Or he might have been warning him out of concern, it was hard to tell with the man. Not that Kurt hadn't known his days were numbered, but it didn't matter. He just wanted to be normal for as long as possible.
Was it so wrong?
A voice inside told him yes. If he didn't stand with his friends he was no more than the monster he appeared to be. It sickened him to the core.
He knew he should stand up for them, he wanted to! But the memories of his past... Having to go through all of that again was too terrifying. He couldn't shake the fear, couldn't let himself get involved with them.
He hated himself. He really, truly did. But he couldn't let go just yet...
A/N: It's always bothered me that everyone was so mean to Kurt after the Sentinel incident. He' probably the sweetest most hypersensitive guy in the group, and they didn't even bother to talk with him about it! GAH! ... The dark past thing? Well, I dunno, I've always seen Kurt's persona as a result of severe trauma. His over-the-top yet highly empathetic behavior is a direct opposition to becoming like the people who hurt him and the monster he appears to be... Or maybe I just like tortured, angsty, emotionally unstable characters and liberally apply that to all of them... -_-;;
