TL;DR: even if your delete script confirms a full wipe and your Reddit profile page shows zero comment, there may still be comments left over (that you can find through a search engine and delete manually on Reddit).
Weeks ago, I used redact.dev to delete all my Reddit comments (thousands of them over 10+ years). Redact.dev confirmed a full wipe, and my Profile > Comments page on Reddit confirmed I had no comment left.
Yet, as of today, Google still returns dozens of results for “$myredditusername site:reddit.com”. It’s not just Google’s crawler lagging; when I follow those links, those comments are still visible on the Reddit website, under my username, where I have the ability to manually delete them.
Thankfully, I hadn’t yet nuked my account, because I knew of other users whose deleted comments got reinstated (although that was thought to be caused by the deletion script exceeding the API rate limit; supposedly a different case, as those missed comments would still show in the Profile page).
spez: edited for clarity.
Okay, I’m not sure where it originated, but here’s a link to a relevant comment. I read it in a post about deleting Reddit comments when I first started exploring the fediverse, and I’m not sure I can find it but iirc, a Reddit admin confirmed that when you check your posts, it only shows the top 1000 and comments are only pushed off this list for “new” additions, and the list is not repopulated when you delete things. Therefore, if you delete all your comments, then check the list, it will show none (or if you delete 100 comments, it will show only 900, etc). Something about how these lists are populated in Reddit’s system. It is also relevant that some of the Reddit delete programs out there use this list and so will never delete all your comments.
I will keep looking for the original post tho.