Earlier quoted context omitted.
You can absolutely delete. You just append data that represents a delete, and the client doesn't show that item or shows it as deleted. Yes, it doesn't remove that data from the chain and a client could easily end up undoing deletes, but if you think that server based deletes actually remove the data, you might be in for an unpleasant surprise depending on the servers in question.
In the case of social media, this isnt enough. Certainly someone will create a client that shows you everything that’s been deleted. Can you imagine if you had used social media since you were a pre-teen and every bit of it was public record? I’m sure no one would use that service.
People redistribute snaps all the time even though they're supposed to "go away", yet people still use it.