Cause the kid was smart. He was pretty average sized, so unless he was the next Bruce Lee, there was no way he could've fought his way out of it. I mean, think about it. The 7 dudes are already beating the shit out of him for no reason. Think about how they'd react if the Asian kid took a swing at the kid wearing a grey hoodie. Plus, for all the Asian kid knows, some of them could be carrying a knife, gun, whatever on them. Better to cut your losses and get your ass kicked, then fight back and risk getting killed...