What the article gets right is that this is not censorship. It's the market not buying the product:
First, only the government can "censor". All other aspects of speaking your mind are simply put...at the will of the people.
Certainly Linda Ronstadt has the right to praise Michael Moore, invite people to see his movie and otherwise support his views. But, with that right comes the responsibility to accept the freedom of speech and the will of her audience.
Her audience paid to be entertained, not to attend a political rally. They, too, have the right of free speech - including the right to disagree and boo her when she crossed the line from entertainment to politics. The hotel who was paying her also has the right to fire her. She was hired by the Aladdin to entertain. Once she crossed the line from entertainment to politics, she subjected herself to being fired.
A colleague of mine is insensed at the caving in of ClearChannel over the Howard Stern problem. He feels that CC is giving in to FCC censorship (the FCC being a GOP lapdog) and that there's a simple solution to the whole thing. If you don't like Howard Stern's act, don't listen. While I agree with that, I also think that ClearChannel has the right to say, "we don't support this type of broadcast, so we're not going to air it." In this case, he's right simply because The Howard Stern Show has been doing the same (now boring) thing for years. Yanking it now is yielding to political pressure.
In the case of Ms. Ronstadt, or Whoopie, Madonna and other "censored" artists, their employers didn't pay for what they got nor did the audience have the opportunity to turn off. Both sides need to take responsibility, blame and credit, for their actions.