For me its having a single instance that indexes all the communites to which all other instances can then pull that information from so when I go searching for communities the I’ll have access to every single one with needing to post the entire URL in the search bar
I’m not saying we shouldn’t be able to hard delete comments, I’m just explaining why the Lemmy developers might not have started with hard-deleting comments. I agree with you we should have the option and it should propagate regardless of any instance settings.
My point in mentioning other servers not deleting your comments is that ActivityPub is an open standard. Technically someone can write a Lemmy competitor that federates with your instance and does not implement the hard deletion of comments. It’s allowable under the protocol. That doesn’t mean the feature isn’t worth implementing, it just means there are caveats to “this comment disappears off the Internet forever” like we’d like.