I'm with you on principle, but as you're aware, there are a hell of a lot of self-iimportant entertainers that like to use their celebrity as a platform from which to spout opinion. I can let most of it slide, but after a while it just gets annoying to the point where you just can't stand the sight of the person. Jane Fonda is a good example - she's managed to alienate quite a lot of people over the years, and many of them have chosen to not support her by making their feelings known at the box office. Celebrities are well within their rights to express their views as they see fit, but they need to be aware that those that are listening are well within their rights to react as they see fit.
Personally, I've never understood why anybody in the entertainment industry would risk alienating such a potentially large portion of their fan base. They come off as putting greater emphasis on their feelings than they do on their career.