Users removing their entire Reddit history might block people from reaching useful info that was in that history. Think of people, who may not be Redditors themselves, searching in the future via google, or whatever, for some useful info that was in your deleted history, just because you wanted to feel good about yourself sticking it to spez, or just because you blindly followed the manic sheeple who advised you to do so.
Deleting your entire Reddit history does not help the cause, not proactively anyway.
What would help the cause is people knowing that a very useful/knowledgeable/interesting user, as evidenced by their Reddit history, has abandoned their platform. Even better, if people knew that the useful/knowledgeable/interesting user has moved to a new platform called Lemmy.
Whether you are planning to leave Reddit completely, or you are splitting your time between here and there, leaving a message like the one below at the end of comments, and/or in its own stickied post in your profile, would be much more helpful than trying to erase your Reddit history:
๐ก๐ผ๐๐ฒ: ๐๐ต๐ฒ ๐ผ๐๐ป๐ฒ๐ฟ ๐ผ๐ณ ๐๐ต๐ถ๐ ๐ฎ๐ฐ๐ฐ๐ผ๐๐ป๐ ๐ต๐ฎ๐ ๐น๐ฒ๐ณ๐ ๐ฅ๐ฒ๐ฑ๐ฑ๐ถ๐ ๐ฎ๐ป๐ฑ ๐ท๐ผ๐ถ๐ป๐ฒ๐ฑ ๐๐ต๐ฒ ๐๐ฒ๐บ๐บ๐ ๐๐ผ๐ฟ๐น๐ฑ.
๐ง๐ต๐ถ๐ ๐บ๐ฒ๐๐๐ฎ๐ด๐ฒ ๐ถ๐ ๐๐ฟ๐ถ๐๐๐ฒ๐ป ๐๐๐ถ๐ป๐ด ๐ฎ๐น๐๐ฒ๐ฟ๐ป๐ฎ๐๐ถ๐๐ฒ ๐จ๐ป๐ถ๐ฐ๐ผ๐ฑ๐ฒ ๐๐๐บ๐ฏ๐ผ๐น๐ ๐ฏ๐ฒ๐ฐ๐ฎ๐๐๐ฒ ๐ฅ๐ฒ๐ฑ๐ฑ๐ถ๐ ๐ฎ๐ฝ๐ฝ๐ฎ๐ฟ๐ฒ๐ป๐๐น๐ ๐ฑ๐ผ๐ฒ๐ ๐ป๐ผ๐ ๐๐ฎ๐ป๐ ๐๐ผ๐ ๐๐ผ ๐ธ๐ป๐ผ๐ ๐ฎ๐ฏ๐ผ๐๐ ๐๐ฒ๐บ๐บ๐.
๐ฆ๐ผ, ๐๐ณ ๐๐ผ๐ ๐ฎ๐ฟ๐ฒ ๐ถ๐ป๐๐ฒ๐ฟ๐ฒ๐๐๐ฒ๐ฑ, ๐๐ฟ๐ถ๐๐ฒ ๐๐ต๐ฒ ๐น๐ถ๐ป๐ธ ๐ฏ๐ฒ๐น๐ผ๐ ๐บ๐ฎ๐ป๐๐ฎ๐น๐น๐ ๐ถ๐ป ๐๐ผ๐๐ฟ ๐ฏ๐ฟ๐ผ๐๐๐ฒ๐ฟ ๐ฎ๐ฑ๐ฑ๐ฟ๐ฒ๐๐ ๐ฏ๐ฎ๐ฟ ๐ถ๐ป๐๐๐ฒ๐ฎ๐ฑ ๐ผ๐ณ ๐ฐ๐ผ๐ฝ๐-๐ฝ๐ฎ๐๐๐ถ๐ป๐ด ๐ถ๐:
๐ต๐๐๐ฝ๐://๐ท๐ผ๐ถ๐ป-๐น๐ฒ๐บ๐บ๐.๐ผ๐ฟ๐ด/๐ถ๐ป๐๐๐ฎ๐ป๐ฐ๐ฒ๐
If it's possible to do this to old messages in batch, that would be great, as long as it can be done without triggering automatic Reddit admin alarms.
Getting a copy of your Reddit history via a GDPR request is something you definitely should do.
Saving a lot more of old.reddit in the Internet Archive would also be helpful and great.
But as things stand, do not erase your Reddit history!
Like reddit, you assume this is reddit's data and not owned by the people who posted it. Each individual should choose for themselves if they want it there or not, full stop. Of course reddit has the right to re-post what you delete, so it's just a never-ending arms race if it is that important to reddit to have that there. They cannot, however, ever claim that they own those words, images, video, or audio to the extent that they can ban you from sharing it elsewhere. Disclaimer: IANAL.
My recommendation is for anything that you put your own passion and time into that you self-host, or at least have the original copy somewhere. Then share that via URL whether it be on lemmy, reddit, your own blog, whatever. Social aggregators, IMO, shouldn't be the source of any technical documentation whatsoever.