Basically men right’s movement are using bad science.

Yes, bad science that considers mutual violence to be mutual violence, and not exclusively women defending themselves from violent men. Frankly, this is just another example of hyper/hypo-agency (basically men are treated as having more responsibility for their actions than they actually might and women are treated as having less - it's the same tendency that plays into women getting lower bail when arrested, lower sentencing for the same crimes, that sort of thing, in this case that a woman engaging in IPV isn't responsible for her violence, but rather responsibility for that violence belongs to the nearest man).

A fun followup for the reader: If women's IPV is primarily defending themselves from violent men, what would that lead you to predict about rates of abuse in gay male and/or lesbian relationships, and does that prediction match reality?

Differences in physical harm basically come down to size/weight and if anyone is using a weapon. This basically means a petite woman should have open season to beat on her SO as much as she wants, but if he raises a hand in his own defense that makes him the abuser - he should just take it indefinitely. Or leave, because leaving an abusive partner is the easiest thing in the world if you aren't a woman (see above about agency).

Fear expression is one of those things bound up in cultural nonsense - it's unmanly to be scared of a girl, so most will process around that or just bottle it and refuse to express it. Related is why NISVS has a bad habit of getting results that suggest that women force men into non-consensual intercourse about as often as men do that to women in the previous year but then wildly different lifetime numbers - give it a few years where you've internalized the message that that's not a thing that can happen to you because you're a man and eventually you believe it.

Hell, I was sexually assaulted a couple of decades ago. Was playing driver for the group, had been up 22 hours because I'd had an early morning and we were doing a late night and when we made a stop for two of the people in the car that was going to take a bit, I leaned the seat back and napped with one other person in the vehicle (a woman). Woke up to her midway through performing a sex act on me, noticing the others were on the way back and her saying "I guess we're more than just friends now." Took me a decade to recognize that as sexual assault rather than just filing it away and trying to ignore it because that's not something that happens to men.