When you download ANY Newstand app, ANY Newstand app at all, you're running third party software that is making connections to third party servers.
Perhaps you believe that iOS is so locked down that the third party doesn't have your info to send to their own servers and monetize? But in the wake of oh-so-many "app uploads all of your info" situations, I find it surprising to believe this.
Yes, Apple isn't forwarding your payment information but that doesn't mean that nothing at all goes to the publisher. They're going to get info on you, both through Apple and through their app on your device. They thrive on getting that info, and more than one is likely going to monetize that info as best they can.
It comes with the territory but please do not think that because Apple handles billing, magically all of your data is safe.