It's a necessary pain in the arse to strengthen the network.
It has pushed effort into web of trust relays, for example.
You can mute/block messages when you see them and eventually they don't show up as much.
Discussion
I don't know if this guy has multiple accounts, but he keeps showing up.
Yeah, he has multiple accounts, so to block/mute him now is a pain because he is posting from multiple free-to-create accounts.
This is why Nostr benefits, because it's another example of Andreas Antonpoulos' sewer rat and bubble boy https://youtu.be/RJWXaWu5MS4