It's not donations. Donations are given without return to a cause you consider worthy. An exchange is promised, but the promise is not a sale, it's "We try and make this, and if we pull it of, you get one." It's more of a high-risk investment where you already consider the money lost, the moment you spend it.

And I'm on your side: It's not kickstarters fault, if people think otherwise - still they could make that point a little stronger.