Hector Martin

I don't think bringing it up at all is the issue; in this case I think you jumped to assuming malicious intent. I agree it's a stupid/insensitive joke, but I think he's poking fun at those who have (unfortunately) co-opted the term "trigger" to mean "think I don't like".

"poking fun at those who have co-opted the term "trigger" is the excuse I always hear, either from those who say it or from onlookers, but I've yet to see anyone who would conclusively and specifically use it in a way that "pokes fun at those who coopted it" while ackonwledging…

its more serious meaning. Never happens.

Ah, but if you're aware that triggering is also a serious issue for some people you likely wouldn't make the joke in the first place (without a big disclaimer that would ruin it). I think for many people the only experience they've had is with the less serious usage.

Actually until recently I wasn't aware that it has a serious meaning, to be honest, but I'm not a native speaker.

These days a lot of people taking care of these psychological triggers seem to use the term "content warning" instead of "trigger warning", probably to distance themselves from the abuse of the latter term.

AFAICT that shift happens simply because people may want to avoid certain content even if they don't have PTSD e.g. I'd put [cw gore] if posting a pic of an injury, doesn't make sense to mark it with [tw]

That's fair enough, but I think there's some influence from the abuse of the term too. There's certainly quite a bit of abuse; I've seen lots of clearly BS claims that "X triggers me", but I think the true sufferers are more likely to suffer quietly.