Seeing that he hit a hydrant rather than a car, I'm going to assume he wasn't doing it around other cars. He crashed and the only damage was to his own car, a simple mistake.
I slide around a tonne in the rain and snow, I've had someone slide into me before, it sucks, but you live and you learn. I haven't hit anyone or anything yet because I try to do it on my own or with some friends away from any other kind of traffic.
Not saying it's the smartest thing to do, but at least precautions are taken to avoid harming others.