Furthermore and finally:
What I consider to be dumb political criticism: there aren’t enough (minority group) in this movie, the author is clearly racist/sexist/homophobic!
Smart political criticism: how is the author presenting these (minority group) characters? is it in a positive or negative light? if negative, is it based on stereotypes associated with that minority group? if the author does not have any minority characters, does it make sense in the story line that he or she would not have that group of people in the story? is the author portraying very surface level characterizations of these characters?