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.
But that's how it works. You should assume everything you've ever posted to another server could someday become public record. Especially with social media since it's being posted specifically to be viewed by others who may copy and redistribute that data at any time.
People redistribute snaps all the time even though they're supposed to "go away", yet people still use it.
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.