The correct framing here is not that Nostr has evil content, but that _some relays_ do.
These relays are not Nostr, Nostr is only the language your client uses to download the content from the relay, and your device only downloads what it asks for and from the servers it chooses to.
nostr:nevent1qqsftruax879q3pdw9x7sknzz6ffxdv42pch7kalw9nz3w5t9ld6j7gpzpmhxue69uhkummnw3ezumt0d5hszymhwden5te0wahhgtn4w3ux7tn0dejj7sq58pj