A moral difference? What even is that? Amazon wants you to put out affiliate links, npp wants you not to. So one is with concent, the other without. Consent is the moral difference?
Apparently you understood what I meant with moral difference, so I don't think it needs to be explained. Consent from the vendors is a good moral difference from the perspective of the right owner, thanks.
The analogy would be creating a site called amazon.org, providing an e-commerce like experience then redirecting people to the real site once you go to the shopping cart.