I'll start a new thread because I lack comment permission on the thread I wanted to reply to. Which is fine incidentally. This is about blocking and webs of trust. If you want to do it right, ActivityStreams (the serialisation format behind ActivityPub) has a Block activity type. This has been there since the beginning. It can support any ActivityStreams object. You can block posts, comments, actors, events , links, photos, instances- really anything. And you can share these activities with all your followers. It's just another post type. This way everybody will know what a bigot you are. Sorry for the sarcasm. But here's the fun part... your software can be configured to show or hide these activities. It can also be configured to prompt you for an action when viewing them. You can ignore it. You can also set it to block everything that this sender blocks, or you can set it to 'ask me'. And you can also set it to 'remember this decision' for any of these choices. And you can do the same with 'Flag'.
All of this can be implemented today without changing one word of the ActivityPub spec or writing an FEP or creating a new service or website.
This is how a free network works.
