Blocking on Facebook is very thorough. If A has blocked B then neither can see the other's posts, comments, or any other comments in threads the other starts, among other things. In many cases this is more thorough than people actually want. The problem is there are at least two scenarios blocking covers:

1. Someone keeps being obnoxious. You don't want to see what they write, and you don't want them to be able to post on your wall or threads, but it's fine if they can see what you write.

2. You dislike someone and want to minimize interaction with them in all forms. You definitely don't want to see their stuff, but you also don't want them to see your stuff, because that might lead to interaction in other ways. Or they're creeping on you, and you want to cut them out entirely.

Blocking is a pretty good fit for (2), but it's overkill for (1). And the problem is (1) comes up a lot: if you have enough followers, or friends who you don't know very well, some of them will be unpleasant. This is exacerbated by Facebook surfacing popular posts into the feeds of friends-of-friends.

This is mostly a problem with how it interacts with people who are central to communities and host a lot of discussions on their walls, or end up spawning discussion threads on other people's posts. These people will have more demands on their time and patience and generally develop lower thresholds for blocking people. The people they block are then partly cut off from the community, and unable to see central discussions without even necessarily knowing that they're missing them.

Now, I'm totally supportive of people blocking anyone they want to if that will make them happier, and I think taking Caplan's approach to the world is fine. But it would be great if Facebook added a "block-lite" that implemented just (1). No restrictions on what other people can see, just on where they can write.

(While I'm proposing changes here, it would also be nice to have something to cover the case where someone keeps showing up on your posts and writing flamebait. Sure, you could block-lite them, but FB could implement something softer. You could say "please avoid showing my things to X" and FB could act as if it had reduced its estimate of how interested X was in your stuff. So X could still navigate to your wall and see what you'd written, and they could tag you in things, but they'd be very unlikely to just come across something of yours, get annoyed at it, and start stirring up trouble. If this existed I would think people central to communties should use block-lite instead, though.)