You are correct.  Movies are not in the PR business, they are in the
business of making money throuhg entertainment.  If films like "Birth
of a Nation" had not been financially successful, racism (and perhaps
some of the other rampant "isms" that palgue our cinematic history)
would have died on the vine.  As long as people will come to see
movies told from one-sided (racist, sexist) perspectives, no matter
how subtly designed or intended, Hollywood will continnue to make these
films/money and reward the filmmakers.
 
Robert Johnson, Jr.