There's always been an imaginary line in the sand that divides art from works created purely for entertainment. Entertainment takes the world of the viewer and spins it in a creative way to delight its audience, or scare them, or wallop them over the head with a heavy dose of sentiment. Art on the other hand presents the familiar world in an unfamiliar way, forcing the audience to come face-to-face with a way of seeing things that, though within them, they don't often connect with and by that process, he or she comes away learning something new about themselves or the world around them.
More and more, it seems our culture doesn't recognize the difference. Either it won't or it can't. But when everything is disposable, it seems the majority of us simply want to be entertained. Yet, with a lack of any sense of reference between the two, we seem to elevate entertainment to the level of art. We also tend to judge art by the standards of entertainment.
I'm not trying to state that one can't be the other. A great deal of art is entertaining and things that were simply meant to be entertaining can be artistic. However, there's a difference between a book whose intention is to tell a good story and a book that is meant to stay with you and affect your point of view on life. It is of my opinion that if you are someone devoting your time and effort to reviewing books and trying to influence people's reading habits, then you should probably bother to learn the difference. But I suppose that may be too much to ask for in our world where the louder you yell is more important than the quality of what you have to say.