Too ridiculous for him
Percy watched them walking away from him again. They'd seemed in a hurry to leave him, eager to reach the pitch rather than to spend more time in his company.
He knew the three of them didn't share the same interests. He'd also study rather than bicker with them yet, as the twins disappeared from his sight, Percy felt hurt.
It was always painful to admit his brothers favoured their team over him. They'd cancel an appointment with him for Quidditch when the contrary would never happen – except if his life was at stake of course. But as long as it wasn't the case he'd keep holding the second place behind their passion, a stupid, dangerous and meaningless game.
A game which had stolen him his whole family. Indeed all but him practised it, or at least loved it.
Sometimes Percy wished such an absurdity had never been invented.
Of course, he could try to get interested in it, he could try to go to their matches, he could... no, to be honest he couldn't. He wouldn't bear to assist to such a ridiculous spectacle.
He wouldn't lower himself to such a low level, not even for his family.