Re: Abuse of power, as simple as that.
"Law enforcement, prosecutors, courts, etc have NO authority to "ask" Amazon to provide the information"
On the contrary. In the US, law enforcement, prosecutors, etc. have the same basic rights as you and I do. That includes the right to ask almost anything of anyone. You can do it, I can do it, and so can cops. If the asker has no legal authority to compel a specific action, of course, the entity being asked is perfectly within their rights to say "no".
(That said, this sort of thing is one more reason why I would never have any device like this in my home or on my person)