Consider it from a customer's point of view.

Comcast threatened to throttle customers' bandwidth, refusing to deliver the speeds they had promised. The data was available to Comcast, customers had paid for the service of delivering that data, but Comcast wouldn't provide the full service they had sold unless Netflix paid them more.

The deeper issue is that Comcast is lying to their customers, promising them more bandwidth than they are able to deliver, so when Comcast's customers wanted to use all the bandwidth they bought to watch Netflix, Comcast couldn't afford to honor their promises.

But Comcast has a monopoly in the markets they serve, while Netflix exists in a competitive market, so Comcast got away with it.