Of course the other side of this is "It's all right not to like". For example a columnist in the Guardian and Observer recently announced, slightly nervously, that he didn't like Wallace and Gromit. Rapidly qualifying that by saying he wasn't criticising other people for liking it, just announcing a personal preferance. (That's what I mean by "slightly nervously".)

Basic groundrule for that wouild be that the item involved would have to be something that is generally felt to be pretty good.