Infinity!

r/gaming has mentioned receiving similar threats, so it might be that more are getting them but by and large only the "edgier" (not meant derogatorily, just can't think of a better term for it) subreddits are going public about it?

Inability to edit or delete anything also fundamentally has a lot of problems on its own. Accidentally post a picture with a piece of mail in the background and catch it a second after sending? Too late, anyone who looks now has your home address. Child shares too much online and parent wants to undo that? No can do, it's there forever now. Post a link and later learn it was misinformation and want to take it down? Sucks to be you, or anyone else that sees it. Your ex post revenge porn? Just gotta live with it for the rest of time.

There's always a risk of that when posting anything online, but that doesn't mean systems should be designed to lean into that by default.