Memories of being suppressed and victimized can be very powerful influences leading to kicking the crap out of someone. Not the black student, it wasn't his memories; but your memories that can lead to future payback. It was racism inflicted on you.
In the late 1960s I was attacked by black mobs and beaten. My blonde girlfriend at the time was thrown down a stairwell by blacks, just for being white. That indeed was racism. If I inflict pain on blacks who get in my face today, I'll be remembering those memories of being suppressed. If that's racism on them, it's racism by them for what they do to whites. After all our memories of suppression are real; theirs are a fiction because they aren't personal.
Who should fear racist actions most: A black man who has a car breakdown in an all-white neighborhood, or a white man who breaks down in an all-black neighborhood?