Arch Linux has always been the butt of a lot of jokes and memes. Anything that becomes popular and has lots of cheerleaders will become a target for jokes. You're just noticing now because it's peaking on attention on the places you look at. It's the natural ebb and flow of memes. It has no rhyme or reason. Trying to predict or explain it is a fool's errand.

Remember, "I use Arch, btw" was born almost the same year Arch was invented. And the first time, it was uttered without a single lick of sarcasm or irony