There is currently a fee bug with Monero, that the wallet doesn’t automatically bump the fee when there is a backlog. This fee bug is causing sync issues with many wallets. The bug has already been solved with Anonero.io, and other wallets will be rolling out fixes shortly.
There are rumors that Nostr's creator is behind a spam attack. Simplified Privacy addresses this and has a ready working solution: https://simplifiedprivacy.com/monero-attack-nostr/
Tor Browser Onion: http://privacypkybrxebcjicfhgwsb3coatqechwnc5xow4udxwa6jemylmyd.onion/monero-attack-nostr/
What makes that screenshot of an e-mail credible? Is there some other more reliable piece of evidence?
Found it! The screenshot comes from the guy himself: https://twitter.com/fiatjaf/status/1576643430306164736