You're not wrong in terms of the average user's intent (they mostly don't care about the source, they care about the content), but I see this as an ethical gray area when search engines effectively offer up all this content created by bloggers without the need of the user to visit the site itself.

Phind tries to ameliorate this a bit by providing a set of links where the summarized data comes from, but most people likely won't even click on these links.

It's going to be rather demotivating when your site's traffic suddenly gets cut in half.