I don't think the majority of the people who do this are male. I can think of half a dozen occasions just over the holidays where this was done by a woman (and I can recall only one male counterexample). She probably sees it otherwise given her politics, but I'd say it's equally split at best.

I do not expect her to make an equal opportunity blog post. However, you wanted to know why it's met with hostility by some people. The post sends out hostility towards men in an unspoken way, so it is responded to in kind.