I came across today one of my own comments on Reddit with a search on duckduckgo. It was still intact. The problem is I used shreddit to randomise and delete the entire contents of my account. My account comments and posts all show empty on my account pages on reddit so there should be nothing.
I did a site:reddit.com search using my username and found ~50 comments that Reddit has undeleted but also hide from my own account. I could still edit and delete them. Its curious that they don’t appear on my accounts content on Reddit and yet a search engine can find them and they are still served by Reddit. Ex Reddit users who deleted their account contents should be aware this is happening and report it as a GDPR breach to their respective agencies if they are in the EU if they too find this has occurred.
Search engines are not live services. That’s old data that Google may or may not ever purge from their index. Using a search engine to determine if your comments are deleted is not going to work.
Just open up threads you’ve posted on in an incognito window. If you’re really paranoid, do it from a VPN, too. If you still see your comments on the live Reddit page, then Reddit un-deleted them. If you don’t, then they’re deleted, but search engines still have that data cached indefinitely.