You’re making a lot of effort here to claim that people should already know this when the evidence here (of people asking what it means) demonstrates that it’s not universal.

For the record, I don’t actually mind people not spelling it out on first use if the acronym is guessable from the context of the comment (which, ironically, a lot of technical acronyms are). But in the case of the OP, you wouldn’t know what SJW was u less you already knew what a SJW was. So it’s not an unreasonable request from the GP. And frankly, the comments criticising them for asking is really unfair. They have just as much right to ask as you do to say “it’s common” and the OP had to use that acronym in the first place. Let’s all just be nice rather than moaning that someone didn’t memorise some specific piece of tribalism before coming to HN.