I'm not 100% sure how it's done, but there is a way to opt-out of the ads served up by Airpush. I think we need to get used to airpush, as it's very dev friendly and it does present a viable alternative to intrusive in-app ads. Without things like airpush and in-app ads, we wouldn't be able to have free apps at all, at least not free apps with any quality. The thing about Airpush is developers get paid, and it costs them absolutely nothing to implement. 100% of their earnings go to them. Here's a link to an interesting interview with the Airpush developers:
Follow-up Interview with Airpush - Developers and Android Users Both Win
I suspect that the same people who complain about Airpush also complain about rich media advertising within the app (it's pretty annoying in the free version of Angry Birds, and negatively affects framerate). Well, the advertising has to go SOMEWHERE.