I always wondered how this was considered a valid reaction to criticism, as it assumes the critics have a psychic ability like precognition or something and comes across as short sighted.

Well, okay it can be valid sometimes but otherwise its basically a knee jerk reaction and comes across as dumb.

I think this trope has one main issue: People can talk about not liking tings without bashing them. Yes, I know there are bash sites, I belong to one for Twilight, but it's more due to a phrase that's on a stamp there: "I love hating Twilight more than you love lowing it". So, in a way, I'm part of almost a reverse-fandom. As long as we don;t troll their groups, why should the fans troll ours? For a less contentious example, I read a book recommended by my classmates a few years back. I didn't like it. I felt there was too much build-up without enough payoff, detail was paid to things that ended up not being important, etc. I told them those criticisms. Most of us had a decent discussion. A couple of them did, however, try to invoke this. I can't unread it, so I will have an opinion on it forever. Just because I'm not a fan doesn't make it less valid.