Why is so hard to understand simple concepts like #YesAllWomen talking about things that virtually every woman has to deal with just because she's a woman and #NotAllMen being a reactionary bit of bullshit that derails the conversation and tries to make it about men, which is PART OF THE FUCKING PROBLEM.
NotAllMen, as an argument, has a simple explanation, though. Namely, that the person replying feels personally offended for one reason or another, and wants to clarify that not all men do action X, or more specifically, that
they don't do action X. It's an argument of self-defence, basically. Is it a poor argument to bring up? Absolutely, since no one is accusing
them of doing action X, except as a generalized class of people, i.e. men, that is understood by the person making the argument to not include every member of that class. Unfortunately, the understanding is not shared by the "defender". ...Unless someone actually is accusing that person of doing action X, whatever it might be. Then explaining that they don't do action X is relevant.