It's because when I'm searching for something I want a link to the original source. I don't want a link to your page, really. The results page would become polluted if it contained links to all agregators such as yours.
It's unfair to be in the results page with somebody else's content when the people searching for that content are actually targeting the original source, not yours.
It's unfair to be in the results page with somebody else's content when the people searching for that content are actually targeting the original source, not yours.