It’s really unfortunate that Lemmy handles deleted posts in this way. It’s one of very few genuine advantages of the Reddit platform. Over there, if the OP deleted the post, the text they wrote would no longer be visible, but all the comments under it still would be. And people could continue to have that discussion, so long as they had the link.
We could have used the tilde, which has been used in formal logic & maths for negation in very many contexts for a long time.
It’s used instead in C and many C-like languages for the far less useful bitwise negation. Of course, we could have had it work in the same way as bitwise vs logical and & or, by dialling up the symbol. Which would have massively improved its visibility compared to the bang.
But for some reason, no. They chose the bang instead.