It was a dumb thing to do. Pierce opened himself up to being tossed, or suspended.
What if Jones then threw a punch? Pierce and him get into a fight that pulls other Celtics in? What if someone's toe leaves the bench area?
We have seen teams lose playoff series over stupid stuff like this.
If Jones threw a punch, he would have been suspended and Pierce wouldn't have done anything as they would have been immediately separated.
Also I disagree that Pierce opened himself up to anything. Players do dumb things and pick up technicals ALL THE TIME. Then rarely do they do anything for the rest of the game in order to not pick up the 2nd (how many games has Perk gotten tossed despite reaching the "Sheed line" in seasons past?). In this case Pierce did absolutely nothing worthy of a toss so I don't know how you can blame him.
As for the foul, I didn't think it was that dirty, Pierce is the best in the league at hitting the jumper after the contact. Jones definitely could have been called for a flagrant after the hilarious call on JO. For the one with Wade, they could have called a foul on either player (although Pierce was set), or a double foul, or the correct call (no call), but to call for a second tech over a screen and some words between captains is just plain stupid. How are you going to screw up the whole game over a pick?