The easiest route to learning about movies, is to watch a lot of movies, and reading about the movie you've just watched. Wikipedia, a more in depth review, interviews with people who made the movie (not just the actors).
Google a top 100 list. Work your way through a few of them. Eg.
Yes, he has a PhD and is a member of the British Academy of Film and Television Arts, the UK equivalent of the Academy of Motion Pictures. No, he's not a snob. Texas Chainsaw Massacre's in the top 10. So are some older classics, which are still good.