The longer version: Look like any busy bar and people crowd the bar to get in close to order. She and he went up to an opening developing when two fat bar bimbos started to leave the bar and one of the fat bimbos stopped short, and blocked access to the bar. That is a foul, a grievous violation of bar etiquette.
That fat bimbo closed the opening gap and that meant the guy was squeezed and only his arm was on the bar as he was trying to squeeze the fat bimbo out of the way. He was not trying to displace the girl, he was trying to get the fat bimbo to move.
People bump and sqeeze at a bar all the time and the female over-reacted.
She is the one that turned with the balled fist and initiated the violence by preparing to strike him. She did not handle this well, as most people know that crowing at a bar happens and not to react like that—raising a fist.
Much like a small guy turning and raising his fist to strike him, the guy reacted and struck the guy/female threatening him.
Nothing unusual but some angry female over-reacting and starting something she could not finish.
You write fiction often?
Without sound, we have no way of knowing the full story. Maybe, like you, the ex-FSU quarterback referred to her as a fat bimbo.
I do note how quickly the ex-FSU quarterback turned tail and ran after he hit her. That’s probably why the team let him go, how’s he gonna stand in the pocket and do what qbs do if he cannot even stand up to a girl in the bar.