Not really. That this doesn't happen to men with the same frequency or degree of severity is enough of a smoking gun to suggest that this is indeed the case.
How do you know that it doesn't happen to men with the same frequency or degree of severity? The internet is littered with reports of/by men being stalked, harassed and slandered.
smoking gun
I don't think that means what you think it means.
Smoking gun is "...a reference to an object or fact that serves as conclusive evidence of a crime or similar act."
I'm suggesting that these sort of attacks on men are extremely limited is enough evidence to suggest the perpetrator is likely to be sexist and/or a mysoginist, which is pretty much the definition of a smoking gun as illustrated.
Think about where the term literally stems from. A smoking gun may tell who did something and what he did. I have trouble imagining a gun (smoking or not) explain why he did it.
fact that serves as conclusive evidence of a crime or similar act...
The fact that I'm asserting is that men do not suffer these kinds of attacks suggest the individual was motivated by sexism. I can't say anymore other than to say that you are wrong. I don't think it means what you clearly think it means. Sorry, no snark intended.
We don't know that. This is an assumption made with no meaningful evidence.