Politicians need that star power. If Trump didn't have it himself, he would never have lasted the primaries.
By the same token, the stars, regardless of their field, need to keep their name in front of people to be bankable. Streep knew that she'd piss off Trump and his supporters. She's now more bankable at the box office because of the outrage. Boycott her next film and even hold a protest at the theaters around the country. In show business, there is no such thing as bad publicity. Even in Polanski's case. I'll get to that momentarily.
It's like when another actor interviewed an empty chair about 4 years ago. Did you hear the hu and cry from liberals about that interview? No, they didn't get offended. They were too busy laughing at Clint Eastwood. I don't think it hurt his career any.
The truth is, movie actors have the same rights as you do, protected by the first amendment. If they don't like a candidate, just like you, they have the right to speak out about it. With the internet, you have as much voice as they do. There are plenty of blog pages available and your memes make a good headline. Utilize those. Build your following, but be prepared to dispute dissenters intelligently.
As for Roman Polanski. He's still a fugitive from justice. The US has attempted to extradite him in no less than twice this century. Both times, the request was denied.
His victim? Now in her 50s, feels she's been raped worse by the press than by Polanski. She did, however, file a civil suit against him for damages, which was settled and has been paid. She'd rather putbthat behind her. Polanski won't reenter the US, eben though there are other avenues of Justice he can pursue, as pointed out by the LA prosecutor's office. He's 84, he'll be dead soon enough.