The problem stems from the fact that the cable companies brilliantly decided to compete with themselves - they sell consumers cable TV, which has a high profit margin, and internet services, which has very low margins. With more and more consumers turning to the internet for TV the cable companies are seeing their profits shrink.
What the cable companies would love to do is charge you more to be able to access Netflix through their internet service, but that would be a lawsuit waiting to happen. As such the cable companies have been light-handed when dealing with heavy users.
The gaping hole with this legislation is that it gives the big cable companies the green light to have tiered pricing, where you pay more when you use more. At first this might sound perfectly reasonable. The problem is that these companies are some of the greediest on the planet and will set data caps unreasonably low such that if you are streaming video (i.e. Netflix) you will be charged dearly.
So while today the internet is just the internet, this would pave the way for an internet for web pages, a separate internet for video, and a separate internet for phone, each with their own charges to get in. All because these giant, prehistoric companies will spend millions on lobbyists to protect the ancient business model rather than actually improve their data services and deliver what their customers want.
We're already getting the shaft, at the mercy of outdated business models. (Incidentally, this is largely the case with the private companies we pay for our other utilities as well.) And this would further slow our progress toward more information available with greater flexibility and speed.