There's a distinct difference between hateful rhetoric and good natured blowing off a little steam, and the examples you give are very clearly in the latter category. I take no offense at these posts because I know that the sort of men they are talking about very much do exist, and I also know I'm not one of them. It's ok they didn't add an addendum remembering that other sorts of men exist; not everything has to be about me.

Also, by taking offense at these posts, you are literally acting out the the second one right now. Got to appreciate the irony of it.

Edit: I forgot to say, the "for centuries" bit is obviously referring to it being ingrained into our cultures.