I've never heard of a case of an Olympic athlete at this stage of the competition bowing out due to pressure. Especially, someone like Biles who many people call the greatest gymnast of all time. I don't know about that (I have no idea who could be the greatest), but nevertheless the worldwide acclaim for Biles made her very famous.
What would it be like to be on a team contending for the championship in some other team sport when your best player decides that he or she can't handle the pressure and bows out?
Simply unbelievable. Unless there's some huge crisis going on in her family that I haven't heard of, there's simply no excuse for what she did. If she knew she wasn't going to be able to compete, she should have dropped out during qualifications and let some other gymnast have a shot at making the team.
She should be disqualified from any further chance at competing for the U.S.
The usual suspects would holler racism, but so what, let them holler. They'll holler racism no matter what happens anyway.