I also appreciate what you say about not confusing "I didn't like it" with "It's not a great work of literature."

Indeed! I keep running into this with regard to my job as creative writing tutor. My students (who don't seem to realise that we tutors sometimes peek into their online forums!) keep saying things like, "Oh, the marking is all subjective. You only got a low mark because your tutor just didn't like it."

No, no, no! I often award high marks to things that are not my cup of tea and that I wouldn't read from choice. And vice versa.