Bringing a gun to a snow ball fight

For those of us who grew up in Canada, the right to throw snowballs at any moving vehicle is as understood as the right to fighting in a hockey game.  But it seems these rights change once you go South of the 49th parallel.  Look at this video about a cop in Washington DC who drew his gun because his Hummer was pelted with snowballs.  You think maybe this guy is a little too tightly wrapped?  If he lived in Canada he could have killed a few dozen kids by now.  Disgusting!!