At this time there are performance and cacheability impacts of blocking members everywhere that preclude us from doing this. In the future we would like to address this better.gator commented
Maybe instead of totally blocking certain users' reviews there could be an option to hide their reviews, like how reviews with spoilers can be hidden. I really don't like seeing "content warnings" on film pages before I see the movies. Being able to simply hide the reviews of users who include these would be a major improvement.