I'm curious why you brought up Breitbart? I just googled it and found a ton of other (non-political/right-wing) sites which drew the same exact conclusion between Schumer and the ending of 5 star reviews. Are you trying to say her thousands of awful reviews were somehow political? Or that it's all just some "alt-right" right-wing conspiracy?
- https://movieweb.com/netflix-cancels-5-star-rating-system/
- http://ew.com/tv/2017/03/16/netflix-star-ratings/
- http://collider.com/netflix-rating-system-thumbs-up/
- http://screenertv.com/television/goodbye-stars-hello-thumbs-...
- https://www.washingtontimes.com/news/2017/mar/17/netflix-cha...
I saw Amy's show live, which she later filmed, and it was just awful. Those reviews were highly justified. And I used to be a big fan of hers before anyone knew who she was.
If Amy Schumer wasn't the original reason why they started to ditch 5-stars then it was most certainly a motivating factor to get it pushed out (conveniently right after her special was famously destroyed - which got widespread press before the switch over to thumbs). As it most certainly also faced internal resistance as they were basically abandoning a decade of 5-star reviews via user-generated-content, in favour of a vague Thumbs Up/Down.
Amy provided a perfect example of the inconvenient and conflicting goals which Netflix has as a producer and content platform. The timing of the release would have been HIGHLY coincidental if it wasn't related in some fashion.
http://www.breitbart.com/big-hollywood/2017/03/18/netflix-sc...
Notice that they're careful to say that they made the switch "amid" the special, not because of it. Also as far as I can tell, they have no actual data on the fact, and they're the only "newspaper" reporting it.