"why do people in entertaiment assunme that everyone in the industry thinks like them?
... if you wanna go for humor like this ive got some for you. songs about kennedy, chapaquitik, "president clinton and bill"....."

And I thought it was short term memory that fails people when they get older.

Guest, you are picking some excellent examples of people and issues on the left that deserve to be skewered.   The earlier mention of Vaughn Meader, Jon Stewart and Bill Maher and I would add people like Jay Leno to that bunch.   They see the humor and the opportunity for satire and they go for it. Frankly, I have yet to hear any of on the "far left" take exception to their brand of humor.   If you operate in the public arena, you are subject to this scrutiny.

As for the folk music community being "left", well there is historical reasons for that. In the 1940's the left did embrace the style - more so than the right - and it continues to this day. From experience, I do think that the majority of the audience that attends their concerts agree with the political view, or have a reasonable respect. Not everyone agrees of course.   Not everyone uses the stage as a soapbox either.

Again, I do not feel this is a left vs. right issue. However, evidence that I have seen seems to show that the right seems to be taking more exception to the humor.