Heck, every day I ride the DART Rail here in Dallas there was some guy like that yelling at the passengers.
On my last ride on MARTA, I had a large smelly guy with dreadlocks standing over me calling me a “G** D*** White Perpetrator.” No one else on the train seemed to notice, though.
Reminds me of a couple of years ago I’m on a packed subway here and some black guy is pushing his way through yelling white people stink. Eventually someone yells back shut up no one wants to hear your crap. No confrontation as it was too crowded to get to anybody and most just rolled their eyes. The guy exited fairly quickly after that. I had a comeback too but like Costanza I only thought of it after the fact. Not sure if I had the balls to respond at the time though.