It makes sense to moderate email based on what server it's from. Alice@spammer.com wants to sell me a mortgage and bob@spammer.com wants to sell me "natural mal

It makes sense to moderate email based on what server it's from. Alice@spammer.com wants to sell me a mortgage and bob@spammer.com wants to sell me "natural male enhancement". I don't want to hear from anyone @spammer.com because that server permits or exists for the purpose of sending spam. There are Mastodon servers that exist for things that most people don't want to interact with, such as racist hate speech, as well as servers that are essentially unmoderated. It makes sense for a server with a mainstream audience to block those.