Just that really - not just men but women do fall into it a bit as well. I see it in, for example, tweets quoting MN posts that are obviously satirical but it's like women can't possibly be satirical, they must actually be serious about it and that neurotic/weird/oversensitive.
I think there's this idea that when women get together all we talk about is men, babies/children and bitching about other women. We can't possibly, y'know, laugh about things and have jokes between one another like blokes do.
I think MN shows how fucking hilarious women can be, but there seems to be this idea that we're all terribly earnest. Yet at the same time not to be taken seriously. Funny that. No pun intended.