She semi-admitted to whaling on his spine while he was asleep to wake him up from his latest stupor. What are the odds that she assaulted him first in a drunken rage for whatever crazy chick reason she had, and he responded to having the most painful part of his body attacked with instant and extreme violence.
She then drunkenly accuses him of assault, because, yes, he did hit her. But then she sobered up, realised that she tore up her meal ticket, panicked and tried to row back, but the Cancel Train had long since left the station.
Is it OK to hit back against a crazy drunken woman who is attacking you in a blind mentally ill rage, especially if you're twice her size, even if she is deliberately targeting a part of your body that is fragile, damaged and incredibly painful? Do you just sit there and take it, even at the risk of permanent injury? Is it reasonable to ask a man to use the minimum force possible in such a charged and complex situation, when you've only just woken up and are in extreme pain?
I don't know. It's a very difficult situation to be in. Those are complex and subtle questions with many shades of grey. That's why Goons are melting down over this, they are utterly incapable of understanding moral shades of grey and need clearly defined good guys and bad guys, even if they have to ... finagle the facts a bit to make it stick. This is what happens when you get your moral education from anime and Harry Potter.