Someone running a relay that I'm connected to through Amethyst is hosting a note, or notes, which link to this content.
I'd recommend relay operators find some way to mitigate this, or use your skills to help law enforcement track down the offenders. You might not be hosting the content but if you're making it available by sharing links to it then you share the same level of responsibility as people running services like nostr.build to ensure it's kept out.