I don’t think they did. Unless you have evidence otherwise, I think this is a rumour which comes from a misunderstanding of how deletion tools worked.

They did it to my comments. I had a like 15 year old account, hundreds of thousands of karma, and I deleted all of my comments that I could view in my profiles history and then deleted my account. Days later I found not only was my account undeleted, all of my comments that I deleted were back as if nothing ever happened - and my account was banned.