Likely an elaborate means of trying to toughen up their kids, and getting them to show more aggression and drive while out there on the ice.
Here, at the name of some hockey finals that you'll read and forget about in 90 seconds, comes a bunch of parents who are really tough and legit and take no shit, because they live vicariously through their children in a way that's probably harmful to the long-term health and happiness of everyone involved. A pretty decent brawl here, made A LOT better if you watch with sound--you really just get a sense with the world you're dealing with. Just way too much class to go around, it's unnerving.
Heads up - real fun doesn't get started till about 50 seconds in.
[H/T: With Leather]