It’s not literally a slur, but because it has developed negative connotations Jewish people tend to avoid it nowadays. Online, you are more likely to see it used by antisemites.
Which is why I think that story is very likely bullshit. It’s from an account that very frequently posts pro-IRGC content, and has previously used “the G word” itself.
A bit bizarre that you're dragging a six-month old post, but I stand by what I said. Nothing in that comment is pejorative.
I explained my reasoning for avoiding the word downthread: https://news.ycombinator.com/item?id=48591986