Bus drivers who do nothing while one passenger abuses another are sadly quite common. I suppose he was more afraid of throwing the kids off since he's probably seen them before and knew he'd see them on his bus again at some point, which would be quite scary. And it's difficult dealing with a pack of young people like that, whether you say something or not it is still likely to escalate the situation. I bet that had any of them been alone then they would have said and done nothing, it's that gutless pack mentality at work where they feel they can get away with some nasty stuff when they're in a group.
