Exactly, if Amazon wants to keep AWS as the backbone of large parts of the internet, they need to be able to prove other business considerations don't affect it

Exactly, if Amazon wants to keep AWS as the backbone of large parts of the internet, they need to be able to prove other business considerations don't affect it - if they ever treated Netflix any differently than another marque client they'd torpedo the trust in them from any organisation who think they might compete in the future.