I saw video of this on ESPN last night...the guy he stole the ball from was literally jabbing his ass back at McGrady trying to back McGrady down, McGrady on the other hand was all over the guy trying to get the ball (no fouling though). The guy with the ball also left his feet twice he was pushing so hard attempting to back him off...At one point McGrady stood back and gave the guy a "WTF" look because he was certainly not backing him down normally, essentially the guy was jumping into McGrady....so he reached around and stole the ball
The taunt at the other end was not as bad as you make it sound, he tipped the ball away from the guy and you could hear what sounded like a whistle. The ball rolled towards the other end of the court but no-one ran after it but TMAC, who got to the other end, grabbed the ball....looked back to see no-one was coming and then dunked it. Verbal trash talking ensued when he returned to the other end of the court.