Completely agree with your analysis of some posting patterns that have been plaguing the board recently, yetanother. Spot on. I'm finding it quite offputting, because I simply can't be arsed to explain the basics of why I believe what I believe to someone who's only going to sneer at it.
Returning to NAMALT, it's a really interesting point. Thinking through it, I wonder if it's something to do with some sort of nurturing/caretaking role with regard to feelings, and that's primarily geared towards men? I think it's a different state of affairs when it's a man or a woman doing it.
I'm thinking of the cognitive dissonance that a few people have alluded to, a sort of not-my-Nigelness that women have of "All men are potential rapists...except my husband, my dear old dad and all of my lovely male friends"? We have to believe that we're surrounded by good men (whether it's true or not), because we'd go stark staring mad if we thought otherwise, and then we'd do what the women-hating trolls on this forum suggest and give up on men entirely, as that would definitely be the logical thing to do.
So we hold the two viewpoints simultaneously - men-as-a-class, and men-in-my-life and we're always precariously balanced between the two. Then when someone hits the right guilt switch, we knee jerk into "not all men" as a kind of guilt reflex to thinking horrid thoughts about our Nigels. But we don't spring into action in the same way when women-as-a-class are traduced, because it doesn't trigger the same cognitive dissonance. I think the contexts in which I would say it are different - it's obvious that not all women are bad drivers, or obsessed with shoes, because I'm one and I'm not, so it's just a bonkers thing to say, and needs no further thought. There's just no need to NAWALT, because duh.
For men, I';d have to guess at the thought process, but it must go something along the lines of "I'm a decent bloke and you're hurting my feelings when you say mean things about men, and I need you to know that my feelings are important". They don't feel the urge to defend women's honour in the same way I think, because it's not casting aspersions on them. And also, shut up women, don't name the problem etc etc.
Interesting question, though. I've not thought about it before, but I've enjoyed thinking it through.