Why did Edward insist on torturing him? He knew that Jasper had trouble with humans and their blood and yet Edward had decided to bring his new girlfriend to their lightning baseball game.
He loved his brother and he was glad he found someone, but Jasper didn’t want to accidentally murder that someone. It was hard enough to go to school everyday and deal with the smell of blood, but this was supposed to be where he could be himself. He was always afraid that if he went back to drinking human blood that his family would disown him, but he was even more afraid of reverting back to the way he used to be before he meet Alice.
So he was angry that Edward had brought Bella not because he hated her, but he hated what he could become if he lost control of himself.