You mistate the concept. I will not pay to see a Penn or Garafalo movie, not because of their politics, but because it is my expression of free speech as a response to their expression of free speech. I have absolutely as much right to free speech as they do.
The old communists used to mistate this concept as you and the neocommunists do. These lefties would not have a soapbox if it were not for their celebrity. I express myself by rejecting their celebrity. And, I can do this because they drive a foreign car, praise the Lakers, badmouth Kazan, or attempt to limit the free speech of anti-communists.
Sean Penn is appearing in "Mystic River", a film by Clint Eastwood. Whaddys gonna do, cover your eyes everytime Sean Penn comes on screen in order to be politically correct?