Even if it was territory (and I don't buy that for a minute), the shooter invaded their space. He drove up to them and approached their vehicle.
No, I don't buy the whole 'territory' thing. Kids blast music. If this guy was annoyed, he should have called the cops. Instead, he took his annoyance and snapped, becoming a cold-blooded murderer. He could have just ignored the situation, walked away, called the police regarding the noise ordinance, turned his own music up, or laughed it off. He went out of his way to be the aggressor in a situation he had no justification in being one.
I agree with you. I was trying to use convoluted logic to make a point.