Violation of "fairness" or pre-emptive "screening" to avoid hurt feelings?

http://www.doonesbury.com/strip/archive/2011/09/12

 Today's Donesbury was pulled in the Chicago Tribnue because the Trib said it "violated its (the Trib's) fairness standards."

Read it for yourself and decide. Was it pulled because it was an apparent scoop which couldn't be verified, or is the Trib protecting half-governor Palin?

I know lawyers who'd argue tooth-and-nail about free speech, and I have to wonder what the Trib's motives were. Doonesbury is executing its own freedom of speech by the cartoonist doing his thing. I realize that the newspapers have syndication agreements and cartoonists have to play by certain rules, but I wonder if editorial cartoons have a different standard. Because they've slammed Obama left, right, and center.

But this strip apparently kicked in some mechanism which caused it to be "verboten" today. The Trib might've considered how much coverage the strip will ultimately get as people pass this 'round the 'Net and jeer at the Trib for its cockeyed standards.