They are AI bots and not real people. They are using the free relays to spam nostr. If you also use the free relays, which you are since I can see you are using them then they are able to spam you.

Are you using nostr elites and nostr band? Nostr band has lots of spam I think they actively remove the spam but spam bots are faster. I'm not sure about the elites relay. I think it's harder for bots to join that relay but I heard they are smart enough to sneak themselves into it.

Try to use only paid relays to avoid spam.