I think everyone should be able to have a voice or an opinion, even celebrities, but I think expressing that voice comes with a price. Celebrities can be polarizing because they have such a powerful platform due to their fame. If you achieved your fame for a particular art, like acting, then in my opinion you should not use that fame as an advantage over ordinary people, who don't have access to the media or press, when trying to further a political agenda.
There are some really great celebrities that keep their mouth shut regarding politics. Of particular note is Mark Wahlberg. He recently said this: “You know, it just goes to show you that people aren’t listening to that anyway,” Wahlberg continued. “They might buy your CD or watch your movie, but you [celebrities] don’t put food on their table. You don’t pay their bills. A lot of Hollywood is living in a bubble. They’re pretty out of touch with the common person, the everyday guy out there providing for their family. Me, I’m very aware of the real world. I come from the real world, and I exist in the real world. And although I can navigate Hollywood and I love the business and the opportunities it’s afforded me, I also understand what it’s like not to have all that.” Compare that to some celebrities that make belligerent political videos and say things to alienate their fans, like, "I want to punch Donald Trump in the face."
By all means, actors, musicians, etc. express your opinions, but remember that doing so comes at a price. No matter what your political opinion or agenda is, you are going to alienate some people. So think about it before you spout off. Does sharing your political ideology or opinion increase or diminish your fan base? Does it help or harm your career, or bottom line goals? If your goal is to get into politics, like Ronald Reagan or Arnold Schwarzenneger, then by all means continue. If your main goal is to be a successful actor or musician, you may want to reconsider. Will the Celebrity Boycott List destroy any careers? No, I don't think so but it definitely makes a difference.