Metafilter has certainly alienated a lot of its community. You can see it whenever it comes up, in a forum outside of Metafilter. Some of its old users show up and often don't have nice things to say. I used to read it (more as a lurker), and remember noticing one day that many of the fun and interesting users had left (verified by checking accounts that I'd remembered). Eventually I left too, after I realized it wasn't a positive thing anymore.