Disclaimer: I own none of this Harry Potter stuff; anything you recognize from the books or the movies is not mine.
AN: None of this is Betaed; I'm the only one who's edited it so sorry for any mistakes.
Because all the initial reactions only got a sentence each and more elaborate ones don't quite fit into the story about Draco's re-induction into the Wizarding world.
Ron Weasley:
No matter what Hermione said he wasn't 'being mature' or 'letting bygones be bygones,' whatever that meant. He hadn't forgiven Malfoy at all, and he hoped to hold a grudge for the rest of his life, but she didn't get what Malfoy had done. Ron wouldn't have done it, he'd rather lose a leg or something than lose his magic. Hell, he'd rather lose both his legs.
It wasn't like Malfoy was a Muggleborn kid suddenly introduced into the world of magic. Malfoy was practically an adult with no parents to support him and he'd cut himself off from magic. There was no support system or other life to go back to, he was alone in a new world with no way out. And if Ron, with his Muggle friendly father, barely understood things Hermione and Harry thought were basic how much worse off was Malfoy? His family probably only mentioned Muggles in passing as scum, none of his friends were even halfbloods. Malfoy might as well have moved to another country were nobody spoke English and no one had ever written a guide book.
Hermione didn't know what Malfoy was giving up. She still had her life back home, her parents even knew about her magic. Giving up magic meant no more Wizards' chess, no chocolate frogs, no flying, no quiddich, no owl post, no floo or apparating, no moving pictures, no St. Mungo's, and no past. If Malfoy walked past the Leaky Cauldron he might know it was there but he wouldn't be able to see it or get in to Diagon Alley. He'd given up the safety that protection spells and wards could provide. And he was at the mercy of the Muggles around him. To them he hadn't even gone to school; he'd never get a job. If elektrisity or a tellyfone or stamps puzzled him they'd think he was crazy. No one would be there to explain things or help him understand things. He might end up as some crazy homeless person who couldn't even dress himself properly, and none of his old friends would be there to help him.
So no, Ron wasn't forgiving him, but he knew what Malfoy had renounced better than Hermione did. That's why he wasn't insulting him, because there were probably had a billion people out there ready to do that for him. Malfoy'd given up an awful lot and Ron had to respect that decision. Even if he still didn't respect the person who'd made it.
P.S. You'd really need to read Going Wizard Again to understand this, but you only need to read the first two chapters.