Dunno TBH. I’m aware of the GDPR but haven’t looked into any implications yet. You can bet that Mark has though, he’s very savvy about such things (he has to be to deal with people being nobby*).
The “right to be forgotten,” AIUI, refers to search engines and not forums, it doesn’t apply here. Which is probably just as well, deleting every post a prolific poster has ever made over a period of years would be an act of gross vandalism, and even if we were to comply there’d be the issue of all the quoted text which would be impossible to remove reliably. And even if we were able to do it, it’d still be in the Wayback Machine and any host of other caching sites.
TD;DR is, if you post on a public forum it’s a matter of public record. If you don’t someone to read what you write, don’t post it. As you shit the bed so you lay in it, or something.
(* – by “nobby,” I’m not referring to the requests themselves but rather the manner in which they’re requested. I can’t think of any which didn’t either contain “or else” in the initial request or in the follow-up when being told no. Third parties are especially good at this, we routinely get threatening takedown orders from Soo, Grabbitt and Runn Solicitors demanding that we remove some link or comment or other from five years ago.)