Netflix doesn't serve streaming video bits from Amazon. The services hosted in AWS are the control plane for getting ui, video and account metadata. Streaming bits (the ones that would allegedly be throttled) come from their Open Connect Appliances in internet exchanges and ISP data centers as well as third-party CDN providers like Akamai, Limelight and Level 3.
tl;dr: this article is full of misinformation and bad investigative journalism