That applies to the current state of deleting notes as well, or anything for that matter. Anything you post on Nostr is essentially public and permanent. We can't enforce relay behaviour, only exclude them, and even that is no guarantee that notes won't eventually be broadcast to bad actors. Currently.
Relays are untrustworthy by default, post accordingly, until we have mechanisms that make it impossible for bad actor relays to continue participating, like Bitcoin nodes.