It is the accumulation of all the dances, scissor kick slides, etc
I can reason it away, sure. But it was a bad look in aggregate. It added to the "Ugly American" stereotype. We may get defensive over said stereotype, but it exists. Take off your I Love America goggles (which I also wear) and imagine if the German women did that to Thailand yesterday. We'd all be critical of it.
I am not suggesting the players should have just been robots out there, but they could have toned it down and still smiled, high-fived, etc. There is a way to do it without insulting them in the other direction as well.