I see both yours and Jimbo's point, but I see the circumstances a bit different.
In last nights situation, the booing and chanting at Papelbon happened during an extra curricula event in which Papelbon was on the SAME team as their Yankees. All players on the AL were vying for the same result. I think that negative reception was different than booing a player on an opposite team in which your playing AGAINST.
It's also being reported that Paplebon's pregenent wife felt threatend during the Red Carpet Parade prior to the game. Now this is what I think Jimbo meant by calling NY fans classless.....
"I feel like I needed to be in a bullet-proof car," Papelbon said, according to the Web site. "My wife is pregnant and she's getting her life threatened. It's stupid."
Be sure to read the Driver's perspective as well.