No different than Apple really, requiring your in-app content to match the lowest pricing available.
IGDA says the Amazon terms limit you to the lowest price "available or previously available on any Similar Service" — it's the "previously available" that's the sticking point.
Tweetbot is having a $2.00 introductory sale on the iOS App Store, where the price will eventually go up. If Tapbots were foolish enough to do an Amazon version, they'd be constrained to offer that price forever. Absurd.
I don't think Tweetbot would have any trouble launching at whatever list price they wanted on Amazon. Amazon isn't selling iOS apps so the Apple App Store isn't a similar service. Google's Android Market would be though.
Your optimism would be touching, if it wasn't coming in the defense of such flagrantly hostile behavior.
Even if this clause did apply only to Android recompilations and not to ports, I trust you'll concede it is not status quo ante with Apple's already-appalling pricing terms.
Apple has a monopoly in the iOS app distribution game, so their pricing terms are appalling for a different set of reasons (regardless of what they are you must agree if you want to ship the app). While I think Amazon is playing hardball, they in no way are the only way to sell Android applications. If the terms aren't agreeable, just don't use their store.
IGDA says the Amazon terms limit you to the lowest price "available or previously available on any Similar Service" — it's the "previously available" that's the sticking point.
Tweetbot is having a $2.00 introductory sale on the iOS App Store, where the price will eventually go up. If Tapbots were foolish enough to do an Amazon version, they'd be constrained to offer that price forever. Absurd.