> Google changed the terms of the Developer Distribution Agreement, I don't believe Amazon was violating Google's terms when they initially put it in the play store.

Whether or not they were depends on what the "primary purpose" of the app was, which is very difficult to objectively determine (since there is no reason that the primary purpose has to be the most prominent function.)

Google changed the terms of the agreement in a way which made them much less ambiguous, which made the Amazon app clearly in violation rather than merely arguably in violation.

Considering the menu option wasn't there for a long time, and was trivially removed from the new app, I don't see how anyone could argue it was the primary purpose.

Well, considering how long they were separate and the little or no user benefit that came from merger of their app store and Amazon's other shopping app (especially post-Amazon SSO), it seems pretty clear that the primary purpose of the merged app was to sneak an otherwise prohibited app store past Google's terms, so...

That's quite a stretch. The purpose of a particular update to an app is not the primary purpose of the app itself.

Amazon weaseled their way around the terms of service, Google tightened the terms in response.

It's shitty on both parts. For one thing it highlights how we're at the mercy of Google's whims. Their terms aren't a bi-lateral contract. Apple's App Store tantrums regularly make the news, but it's clear Google has exactly the same power.

For another thing, it was a pretty stupid thing to try to do for Amazon, and can be interpreted to show how desperate they are.