You forget that the kindle isn't an app, it's a device, and the convenience of the kindle on alternate platforms is just that. It's still simply added value to those platforms which get the app. This won't hurt Amazon -- they'll pull their app and Apple will lose some value on their platform.

Realistically, it has cost Amazon nothing to support the iOS platform other than a few weeks of dev time to build the app and deploy it to the store. Complying with these ridiculous demands would cause a zero cost platform to suddenly have a very noticeable cost.