The post is complaining that the counter movement #notallmen is obviously right, and also that it's a trite counter argument to what is assumedly (and commonly) a claim of "all men X".

They are arguing that "All men X" should obviously not be taken as literally "all men", but as a shorthand for "systemically enough men that the behaviour continues to exist so that almost 30% of men will do X at some point in their life".

And that anyone saying "well, not all men" just isn't listening.