Makes sense to me. The point is that the speed test traffic pretends to be netflix traffic which is mainly download. The upload to other servers could be limite

Makes sense to me. The point is that the speed test traffic pretends to be netflix traffic which is mainly download. The upload to other servers could be limited by the ISP while being unlocked for netflix with low cost (because people don‘t upload a lot towards netflix). So there is less signal in the fast.com upload speed measurement