A celebrity has "more" free speech rights than the rest of us. By being famous, getting high ratings, big selling movies, they are allowed greater access to the public forum to express their views.
It is counter-productive to pay money, watch a show of somebody who trashes what you believe.
If 1,000,000 people who support the war, go see a Janeane Garafolo movie on it's opening week-end during the evening, her movie generates $7,000,000 just from war supporters. She then gets magazine show interviews where she gets to express her loathing of the views of her audience, while those 1,000,000 people collectively have less of an outlet than she does.
Same thing with liberals. Why would liberals want to pump up a Charlton Heston movie, so he gets splashed on the tv, gets a ton of money in his pocket, always talking up guns which they loathe.
I actually don't care about a celebrities political views, if they mostly keep it to themselves. I don't screen electricians, plumbers, gardeners for their views, but then again, they don't ram it down my throat either.