There were a number of scripts that would take your login, work backwards, editing each comment in your history to something generic and useless before deleting that comment. After all the comments were edited & deleted, the script randomized your PW and deleted your account.

There were sites to do this during the '14-'18 reddit revolts. (I believe these sites used the reddit API, prior to the API being locked down.) These days, you'd have to go looking in gits for the raw code to execute, which gets a bit sketchy.