I think this is something a lot of people would appreciate. I do myself, considering the random child pornography posts I see people spamming. Thinking out loud, this could be a feature that you can toggle off, but it would be a power user feature. The feature would remain on by default because people want delux by default and only power users will customize, others just complain and run away. Another thought, I think the use of the follower list is now overused. We probably should be able to tag users and then we can apply rules like this based on the tags. This way we can say "Dave hates the same shit as me, if he blocks something, I don't want to see it either, but anyone else I follow are not my personal mates".