Coming from the perspective (for better or worse) of someone with some exposure to feminism but not to the point of hearing the term "rape culture" frequently or anything like that – I can't agree with this. I basically agree with the grandparent. A joke that an innocuous presentation might be considered "offensive or part of rape culture or something" seems to me to derive its humor from a stereotype of people taking offense at things too easily and throwing around the term in question. If he were to speculate about, say, whether the presentation might be taken as encouraging gun violence, the joke would be nonsensical, because there would just be no reason to think it would. (In that case, an analogous situation would be if the presentation were about guns in video games, where he'd be having fun at the expense of an old tired trope.)

To be fair, no matter what you think about feminist issues, it's simply factual that they're a hotbed of emotions, that many people will get worked up about them very very easily, as had been recently demonstrated in the mailing list thread. There's no shortage of similar pure tech issues - things like systemd vs. Upstart or BSD vs. Linux. In those cases, just about anyone would admit that the relevant flame wars tend to derail discussion and give off more heat than light, and similar jokes might be made causing little offense. But with the issues at hand, to which perceived trivialization in culture itself makes up a large part of the problem, there's a fine line between reacting to this phenomenon and making oneself an example. And as long as a joke can be reasonably interpreted as the latter, I think it would be far better to avoid it.