Freedom of speech, or censorship via sales

I was just thinking the other day about artists/celebrities who speak out on controversial issues, and the proper way to respond to statements you may disagree on as a private citizen. The two examples that come to mind are the Dixie Chicks speaking out against George Bush at the beginning of the Iraq war (in retrospect, I think one of the bravest stances I've seen, given their audience), or Tom Cruise railing against psychiatry.
How does one express support for, or voice disagreement with a celebrity who makes a stance on an issue outside of their line of work without doing it through sales? Having lived with depression for a number a years, I couldn't have disagreed more with Tom Cruise's stance that it's all false, and that they're trying to control us, etc. Knowing I'll never have the chance to debate him on it, the only recourse I thought I had was to stop seeing his movies (and I have pretty much done that, with two exceptions - M:I3 when my roommate Jon talked me into going, and Tropic Thunder, which I got from the library). The Dixie Chicks perhaps stand as the best example of this in recent memory:
http://en.wikipedia.org/wiki/Dixie_Chicks#Political_controversy

The problem with this angle is that people aren't necessarily going to buy albums/movies/etc of people whose views they support, so it becomes a one-way street in which it's a bad idea for entertainers to speak publicly on anything controversial (or take a controversial stance on a normal issue) . In essence, it becomes censorship of anything you oppose. I don't want to endorse censorship, even though I think ignorance (or since Cruise claims to have done all the research on psychiatry, just drawing incorrect conclusions) broadcast through celebrities often carries too much weight, and is harmful to many people. I don't want entertainers to be afraid or discouraged from taking potentially unpopular stances, because of the power they have to do good things (see George Clooney, Don Cheadle), so what other options are there?

Propaganda versus making a point

This morning Micki and I were discussing Ayn Rand as a result of Rosh's quote on Facebook. When I made the point that Rand can make extreme examples to make her point, Micki argued that it's propaganda. At first I disagreed, but upon further consideration, thought that when you write a novel, and are therefore also writing the opponent, you can make them do whatever you want, so it's not necessarily a realistic (and therefore valid) example. So my question is, where does making your argument become propaganda? As a continuation, where does taking a side become propaganda? An example could be news organizations. No one will argue in situations of genocide that it is wrong, and that is how it's reported. They might report the quotes of those committing the atrocities, but it will likely be reported in terms painting the situation as wrong (which it obviously should be). But say Fox News takes the angle that stem cell research is wrong (I don't know what they've reported on that), and reports on the topic from that viewpoint. Many would call it propaganda, while others would say it's the right viewpoint. Where does the line get drawn?