Because I feel like Hermione is more bad-ass than people think and she wouldn't have just sat silent throughout the whole year in class.
"Psst," Ron said quietly from behind Harry. "Harry, mate." Harry still didn't look up from his book - which he was reading with stiff shoulders - and Ron was forced to resort to violence, kicking the back of Harry's chair.
The emerald eyed wizard whirled quickly, glaring at him which Ron didn't even bat an eyelash too. "What?" he hissed.
"Look at 'Mione," he replied and realised that all the effort to get his attention just for that seemed a bit stupid but he wasn't going to back down. "Isn't it strange? She looks almost mad that she's being forced to read!"
Harry looked over at the witch in question and agreed. Her jaw was clenched and her eyes were glowing with a magic that he'd been on the wrong end of many times before. Her knuckles were white as she gripped the book and he could see that the force she was gripping the book with was starting to damage the cover. The inside pages were already torn.
"What's that all about?" Harry asked in disbelief, forgetting his own madness and having to read instead of doing anything practical. He knew Hermione hadn't been too impressed with the idea of theory being everything but it was still time for them to just sit there and read. That was something she normally grabbed with both hands.
"I have no clue," Ron replied, eyes fixed on Hermione. He watched as she finished the page she'd been reading and turned it with force that caused it to rip; the quiet noise was loud in the silent classroom and every eye turned to her. Many, if not all, in shock that the bookworm could do such damage.
"This is ridiculous," Hermione hissed to herself. "Excuse me," she called louder, attracting the attention of their Professor. "This book contains no practical content. Even if we were just doing theory all this year, there is still no way for us to learn anything practical come our O.W.L.s."
"hum hum. I don't see the problem, dear," the sugary voice replied causing everyone to cringe. "When encountering a problem, you should alert the Ministry."
"Oh, I would, but you see, I am not aware of any way to contact them when in the middle of a dangerous duel because I haven't been taught them," Hermione replied, smiling sweetly. "It's rather brilliant what you're planning here though. Keep all of the students defenceless and then when they do get attacked, they'll just have to suffer an injury and possibly die!" Hermione mock gasped at the pink woman. "I wonder who would get blamed for that."
"Detention, Miss Granger!" the shrill voice squeaked, her face sporting a patchy blush. "Now class, return to your reading."