http://blogs.wsj.com/speakeasy/2011/04/17/atlas-shrugged-earns-1-7-million-at-weekend-box-office/
Apparently, it did pretty well for an independent film. Yes it has an 8% score on RT, but it is not the critic who counts. According to RT 85% of the audience liked it. Thats the feeling I got from my friends who have actually gotten to see it.
Edit:
I'm guessing its because anyone who went to see this movie supported its message and would have liked it regardless of how entertaining it actually was.
well of course ^_^ . So we can conclude it communicated the message fairly well without being totally off-putting I suppose.