Why not debate which is better, chocolate or vanilla ice cream?

That's not a valid analogy - the preference of food depends entirely on taste, the evaluation of movies also includes a great portion of thought, argument and attention.

I.e., I may watch through a movie while eating pizza and get high on happiness hormones, but miss a lot of bad stuff that might have downgraded my opinion of the movie overall had I noticed them.
Hence, me saying "wow, this movie is awesome" is worth less than a thought-out review focusing on its various aspects. I'm only good enough to say "this movie is good to have fun for two hours with a pizza and lots of green tea".

Having that all said, don't you think you're acting a bit too defensive for a dude who started his own thread about 10 reasons why chocolate is better than vanilla ice cream? :D