Canada has the best 3 players in the game. McDavid, MacKinnon, and Makar. But the US has the best goalie in the world in Hellebucyk. In a short series, like this tournament or the Olympics, having the best goalie matters most and the US has him. Couple that with Canada already without 2 of their top 3 defense and maybe without Makar tonight too, I don't think Canada is strong enough defensively and in net to hold off the US.
I think the 5 on 5 play will be pretty much even, but Hellebucyk will make most of the big saves and Billington (CAN) won't. The US advantage in net is massive. I think the US wins the tournament too. This might be the best US roster ever, at least up there with the 96 team.
As for the booing, no one is booing Americans. They are booing one man. If the leader of another country threatened your sovereignty I hope every one of you would boo that nation's anthem as well.