Ron Artest, like Brandon Marshall, has psychological problems.
It's a medical issue, not a joke, and he's on medicine for them. Part of him changing his name was to begin walking a new path. In a way, his name had become radioactive. It doesn't have to work for you any more than his shoes have to fit your feet. I watched him later in his career on the Lakers and it was clear how far he'd come.
As far as the brawl, the history of those teams went way back and that game and that moment didn't and doesn't exist in a vacuum. Reggie Miller and later Jermaine O'Neal were in their share of scraps and Detroit cultivated the "Bad Boy" image going back to Bill Laimbeer and Dennis Rodman.
Part of the reason Ben Wallace took such umbrage to the hard foul is that the Pacers were up 15 at the time with less than 50 seconds to go, so a Wallace lay up was a meaningless score. To commit the hard foul there was more about sending the message that "we're going to crap stomp you and disrespect you in your own house right up until the final whistle. In effect, there would be no gentlemen, no concessions, no give whatsoever in this rivalry. Well, after a hard night and a clearly losing effort at home, Wallace had had enough. Not to mention, there is something about certifiably crazy people and defense in the NBA. Rodman was another. Both he and Artest had the ability to drive opponents mad. Artest could also score.
The NBA learned from that and they keep a MUCH tighter rein on games now. Maybe too tight, but this brawl was a big part of why.