I just spent all day today fighting with reddit, trying to get all my comments deleted/overwritten: https://kbin.social/m/RedditMigration/t/45417/Anyone-have-experience-with-deleting-comments-to-see-older-comments#entry-comment-190482
It's not just me, someone else reported the same, though using a different tool: https://kbin.social/m/RedditMigration/t/46805/Strange-phenomenon-while-deleting-my-comments
Basically, reddit has the most ridiculous api ever! A 1000 limit on viewing .. well basically anything. Try to go further back, and you can't.
The tools and scripts and websites we are using to delete, they are hitting that limit and can't go past it. My own reddit is only 5 years old and I hit this. I imagine that many folks where, the ex-redditors who had 12, 17 year old accounts, you probably didn't get everything on your way out.
Unless of course, you had a data retrieval request made to reddit, and reddit responded with your data. Only then are tools like shreddit and websites like shreddit.com able to completely wipe out your history. Or else you knew about this somehow already and used an external manager like eternity - https://github.com/jc9108/eternity - to save a copy of your posts before they got lost to the 1k limit.
Worst of all, it's explained that deleting items does not rebuild the list - so you can't see the older stuff by deleting newer stuff.
I'm hoping that private/public transition is an exception to this and it'll rebuild my lists when that happens. Maybe then I can go far back enough to delete everything.
Edit: Nope, someone confirmed in a comment below that this doesn't happen.
Also looks like pushshift is not an option, as pushshift was shut down last month, https://old.reddit.com/r/pushshift/comments/13mhuzq/api_has_been_taken_down/ - and under the new deal, regular users won't be able to use it when it opens up for business again, only approved moderators can (and likely only for approved reasons) if i'm understanding https://old.reddit.com/r/pushshift/comments/13w6j20/advancing_communityled_moderation_an_update_on/ correctly.
Can you find the cite for that? What I found from hackernews (and saw something similar on a subreddit that was supposed to be from a reddit dev itself) says differently. More like an index limit than a display limit.