From what I recall, Pierce threw up a peace sign as Scal pulled him away. Saying he threw up a gang sign is ridiculous. Now of course it wasn't the hippie love everybody peace sign, it was the i'm gonna get you peace sign. And honestly, if the refs had done their job and called a tech when horford pointed and yelled in pierce's face or when he went out of his way to get the ball after a block and dust it off, I don't think pierce would have reacted this way. The refs need to be more on top of this stuff. The players are going to get caught up in the moment, the refs shouldn't.
It's the playoffs baby! Has everybody already forgotten all the talking, posturing, and yes even fighting that our beloved celtics of the 80's used to get into. It's what happens when you play the same team in a 7 game series. Do you think Bird would have just stood pat if someone got in his face like that and the refs did nothing...not a chance!
This kind of stuff is going on in every series. I'm not saying it is sportsmanlike, but it's what makes the playoffs the playoffs. Sit back an enjoy!