I mean web of trust, wtf is it really?... One user might find someone's 'untrustworthy'. I see why a user would want to curate their own feed, I'm sure we all agree with that, but to extend that to someone just cos they follow them, nah. I'm not going to agree with everything personal and political of the people I follow.
There is also an obvious problem. You have clients where they have autofollows on signup (not knocking this). Then you have a client like amethyst that has a mechanism where of 5 people you follow block someone they are blocked for everyone following them. I'm not saying it is currently exploited, but it could very easily be. Not to be all tin foil hat lololol. But generally adopted blocklists suck. I can happily make my own mute/blocklist.