American announcers being homers is nothing new. It's why Olympic coverage is often unwatchable.
American soccer commentators seem to think (wrongly) that the US actually is among the top 8 in the world, so the idea that they crashed out of the group stages of Copa America is *really* bad to them. This was supposed to be America showing the world that it could win against real opposition, not just the weak sauce in CONCACAF, in the lead up to the 2026 World Cup which they are hosting. For bonus fun, check out the meltdown by Taylor Twellman after the US failed to qualify for the 2018 World Cup. The mentality hasn't changed.
The other thing that adds to this, among followers of the US men's national team, is that Canada's new coach, Jesse Marsch, is an American, and was briefly in the running for the national team head coaching job a couple of years ago - when they decided to just rehire Gregg Berhalter instead. So there would be some on Fox, likely, who are thinking that had Marsch got the job that he would have led the USA!USA!USA! to the semis, rather than Canada.
I hope Canada upsets Argentina so they can cry harder.
John