The concept of “deleted” is not black and white, it is a continuum (though I agree that this is a very soft delete). As a technical matter, it is surprisingly difficult and expensive to unrecoverably delete something with high assurance. Most deletes in real systems are much softer than people assume because it dramatically improves performance, scalability, and cost.

There have been many attempts to build e.g. databases that support deterministic hard deletes. Unfortunately, that feature is sufficiently ruinous to efficient software architecture that performance is extremely poor such that no one uses them.