Um, because the team with the better +/- (or minute-weighted +/- per player) wins each game.
On an overall team basis, I can see that. As in "team x is (+/-) team y in rebounds". But on an individual basis, its way too easy to misconstrue and take out of context.
<< shakes head in pity >>
You really enjoy being an arrogant, condescending prick, don't you?