I have 100's if not many thousands of options to buy from when it comes to Amazon, but yes, Amazon is ultimately responsible for what they sell and - surprise - we have laws against counterfeit merchandise sold as if it were the original brand. So yes, Amazon has some duty here.

Apple does not have the same kind of duties when it comes to apps in the Apple app-store, they have created a de-facto monopoly on the channel between the people programming applications for ios and their customers.