Oh but you can...there's a tool for that
Discussion
which one??
nostr:npub1aeh2zw4elewy5682lxc6xnlqzjnxksq303gwu2npfaxd49vmde6qcq4nwx made a "nuking" tool the other day that I haven't tried yet. Of course, some relays may ignore, so your claim is likely still accurate, but might be worth checking out.
It’s not guaranteed to work with every relay, but it gives you more coverage than your client’s (request) delete button (if it even has one).