I've seen this post linked at quite a few of the blogs I read on a regular basis.
To a one, the responses/reactions are positive.
I'm going to be the odd-girl-out.
Celebrities have just as much right to open their pie-holes as the rest of us do. So what if they are professional liars? So what if their job is entertainment? They are no better and no worse than the rest of us. The First Amendment applies to them the same as it does to me and to every single person on my blogroll.
Would it be acceptable to say to my husband "You work at Wal-Mart. Your job is to keep your section clean and help me find merchandise. I don't care what you say"?
Would it be acceptable to say to AlanDP "Your job is to read my water meter, not comment on _____"?
Would it be acceptable to say to AmbulanceDriver "Shut up and intubate people"?
Of course it wouldn't. It's no more acceptable, then, to say to any celebrity "You exist only for my entertainment. Keep your opinions to yourself."
Do I think any of us should care what a celebrity's opinion on Issue XYZ is? No. But they actually are real people, inasmuch as anyone else is (I don't exist outside the computer for most of the people I communicate with). They get to shoot off their mouths just the same as the rest of us, and we get to roll our eyes and ignore them, or mock them, or quote them if they happen to say something we agree with. Just the same as if they were John Doe off the street.
Holding yourself above an actor because you're "real" is frankly just as idiotic as looking up to them because they are famous.