After 13 years, I had quit reddit 1st June 2023. At the time I joined beehaw (lemmy.world didn’t exist) and used the redact utility to delete all my posts/comments (we could at the time delete instead of mass editing.
I lurk sometimes some niche communities or go on reddit from google search, I never comment or upvote. I sometimes click on my user to see there was no comments/saved/etc.
Yesterday, randomly, I clicked on my username and saw all my 2023 and less post, 13 years of comments, I was like WTF, after 2 years, reddit decided to take an old backup or something and undelete all my comments!!!
As now redact only do mass editing and pretty slowly, I used something else, https://github.com/Jelly-Pudding/ereddicator/tree/main, followed instructions, it deleted ~3600 comments in less than 2 hours.
I’ll monitor from time to time if reddit keep undeleting them, to feed their AI…
They have backups. Even if your old comments and posts stop resurrecting and permanently become invisible to the web, Reddit can do what they please with their backups, including selling them to AI companies. It stops the scrapers, sure, but then Reddit wants the scrapers to stop as well.
GDPR removal requests are worth a try, but they technically only cover personally identifying information, so you’d have to make a strong case that your comments in whole or in part could be tied back to your real self. And they could get around most of the edge cases there if they were to anonymise that information further, such as by disconnecting each of your comments from any commonality.
This is part of the reason I never bothered to delete anything over there. No point closing that stable door. Those horses are long gone.