Pfft, everyone else was going too slow.
I dislike that his fine comes down to other people's inadequacies. They think "I couldn't skate that fast safely, so an old man - who is skating pretty damn well - certainly wouldn't be able to.
I agree that it's not the smartest place to skate and someone could get hurt, but they didn't. They should have told him not to skate there again and suggested he gets an mp3 player.