Some givens regarding this Gergg/Gio crisis:
Gio can be a pissy little bitch. Anybody who's watched him can agree with this.
Gio's parents seem overprotective and enabling.
Gergg did not deserve having a minor domestic something-something from 20 years ago brought to light. It was purely awful and prejudicial on the part of Gio's parents (mom?).
NEVERTHELESS, as others have noted, Gergg did fire the first shot by publicly--and quite unnecessarily--embarrassing Gio several days after the USMNT's World Cup experience had ended. Gergg's passive-aggressive comments were unprofessional and, to me, seemed like an attempt to throw one of his players under the bus as a means of deflecting criticism away from himself.
Furthermore, as coach, it is Berhalter's duty to be the bigger man here. Yes, Gio can be a little shit, but he's a prodigal talent and a net positive for the team. Sometimes, a coach has to set aside his ego and compromise.
And that's my key issue with Gergg--he is prideful and arrogant despite not having any reason to be. His coaching record is meh, his tactics are often questionable, and his roster/lineup management is abysmal. Finishing third in qualifying (and tying on points with the fourth-place team) despite boasting the deepest and most talented roster in USMNT history, despite Costa Rica being older than Gianluigi Buffon, despite El Tri being a shambles, and despite upstart Canada having no depth is nothing to hang one's hat upon.