That's why "Amazon can do better." Not to act more altruistically, but to do better. If they keep doing things like this, it won't be good for them.
So clearly Amazon has no moral scruples about doing what they did, but to us (or others) it's ethically ambiguous.
Dude, they picked a software project that was released to the world under a license that explicitly allows anyone and everyone to use it as they see fit, and they proceeded to use the software.
Please do explain exactly wheredo you see any breech in morality.
So, a person may be clear morally, based on a code of values that puts an emphasis on a legal aspect of interactions between people, but from the perspective of ethics we can observe that such a code may not be sufficient to fully realise their potential of flourishing as a human being.