The advice to a woman who is hit by a man is to de escalate, get away, tell someone, get to safety, assuming you are able (not incapacitated).
The advice to a man who is hit by a woman is hit her back. Or hold her off.
The power balance is obvious in the advice. It assumes that the woman is in way more danger than the man.
For individuals, and rarely surely, in an outside the pub, unarmed situation that we are talking about here, this will not be the case.
But why we are being told to ignore the obvious difference in beyond me.
Maybe it's because I am on the small side, I know that I would lose a fight with any man, and fast. I have been punched in the face by a random man, I went flying through the air literally (left the ground) landed on my back. Suspected fractured jaw. I am not tiny though. 5'3 is small side but not remarkably small by any stetch.
No one should hit anyone. Obviously.
To say its equality that men should hit women back, when women are never advised this (and we all know why), while still claiming that its exactly the same is silly.
Are women as a group as big, strong and violent as men as a group? Apparently avoiding to equality we must ptetend they are, and women who hit a man and bruise him are as bad as men who hit women and kill them. As suggested upthread.
This is all silly.
No one should hit anyone.
But.
Consequences matter.