While I agree with others that it is perfectly fine for everything to be irrevocable like email is (there’s no real way the system could work otherwise), I do think the Lemmy web UI and popular Lemmy native clients could do a better job making sure users are aware of that. Maybe when writing a comment there could be a little info bar that says “Content posted to Lemmy cannot be permanently deleted. (Learn more)”. And then when you click Delete on something, it could have a similar explanation, adding something like “Deleting this comment will remove it from the feed/thread, but it can still be retrieved from the federated database by any instance administrator. (Learn more)”

I think it is still useful to have a Delete function, or maybe rename it to “Remove” or something, because maybe you realize what you wrote isn’t contributing to the discussion or for some other reason isn’t useful for most people to have in their feed. There’s a difference between deleting data and removing content from the canonical “discussion”, and just because we can’t have the former doesn’t mean there’s no value in the latter. Also, the delete function does have meaningful effects like making it impossible for people to reply to the deleted comment, which can still help with harassment. 99.9% of users will never see that comment again.