Actors make movies and thats it.
That's the thing, if that's all they did a little opinion difference wouldn't matter. I also wouldn't care. That's not what they do though, they use their money and fame harm others. He went on Glenn Beck to support his 9/12 movement, was outspoken about being anti-lgbt, and donated money to those causes. Similar to JK Rowling, who some say to just ignore, then she also started donating her wealth to bigoted causes as well.
Assuming rich and famous people's opinions can't cause actual harm is just ignorance.