This is a valid concern when the carrier asks for money in exchange for "enhanced" fast lane service. However, in this case T-Mobile is undermining that argument completely by offering "any website or mobile app that offers streaming video [to] opt into its program with no charge. And T-Mobile users can turn off Binge On at any time." (Emphasis mine.)
In a nation where most people are served by what is effectively a non-competeing cartel of companies, allowing strong anti-user incentives to exist is a very bad idea, because they wont just be out-competed by a less exploitative company.
I generally agree with you about non-competing cartels of any stripe, but this particular case seems like it was designed to be consumer-friendly to T-Mobile's short-term financial detriment. Perhaps additional two data points will help:
1) Carriers (both fixed and wireless) that are not #1 in market share will sometimes engage in loss-promotions or tactics to gain subscriber share. The question often turns into "how long can X sustain this strategy, and how many subscribers will they lose when they're forced to downgrade offerings?"
2) American carriers are at war with each other, to the benefit of end subscribers.
Eg, they will keep data caps tiny, because its better for them if every service with a lot of data usage comes to them to pay for a bypass. This is categorically massively punishing to smaller players without money and connections.
In a nation where most people are served by what is effectively a non-competeing cartel of companies, allowing strong anti-user incentives to exist is a very bad idea, because they wont just be out-competed by a less exploitative company.
Perfect isn't being the enemy of good in this case, "good enough" is being the enemy of things meaningfully improving, ever.