Its a very common expression. I don't know if 0bama meant to call Governor Palin a pig or not but the crowd took it that way.
It seemed to me that he was referring to the Governor though. He probably thought it was a lot more subtle and nuanced than it turned out to be. The Dems have been using the 'lipstick' buzzword for days alluding to Palin's joke about hockey moms.
People can run with it if they want to but I don’t see where all this sensitivity is going to get them.
Any reasonable middle of the roader who understands the expression is probably NOT going to take it as he meant to call her a pig.
But it sure will fire up the base!