You know, I also hope that Jon is never "forced to delete posts" by the all-powerful forces of political correctness.
But I'm not too worried, since they don't, well, *exist*. And even if they did, I trust our editor's ability to judge how to best exercise his, well, editorial powers -- is there some reason you don't? (Though you do seem comfortable assuming that external pressure is the only reason he would ever decide to delete sexist posts; on this point I am less convinced, and anyway isn't it rude to threaten him like that? I mean by implying that if he ever took a more actively anti-sexist stance then everyone would think he was a wimp.)
I'm sorry if you didn't notice, but sexist behavior is a fairly topical issue right now, and anyway, being "on topic" is not more important than treating other humans with respect. But it doesn't even matter, because you agree with wingo that "carry[ing] part of the load for lwn's tone" is in any case a good enough reason to make an off-topic post. So if you want to criticize wingo's doing that, I think you need to do more than just complain it was off-topic, or you just look like you're applying a double-standard.
I understand that fundamentally your argument is that the sexist joke was no big deal, and anyone who thinks otherwise is some mindless political correctness spouting drone. I disagree with both claims, wonder whether you actually have any support for either, and suggest that whether you found the joke "easily ignored" is not actually the final word on its importance.