Because it's not their fault that the referee screwed up. Even without the penalty shot goal Rapinoe got them back even twice. Because they were arguably the stronger team (except they could not contain Sinclair).
My only beef is against the ref, NBC coverage and that one US player who made the diving hand gesture when one of the Canadian players got injured. Unsports(wo)manlike, especially in soccer. On that play the two players went up and when they came down the (somewhat large) US payer's foot came right down on the Canadian player's foot. That wasn't just stepped on, when only half the weight is on the foot, it was full weight, assisted by gravity. Yeah, it probably hurt and she stayed down for a bit. But come on, this is soccer.
Other than that, I have no beef against the US team. Did they play a bit rough? Only as far as the ref allowed them.