Net neutrality supports entrepreneurship, startups, and therefore competition. Dumping net neutrality is inherently anti-competitive.
If I want to start up a video streaming service, I will be gouged by every ISP out there. I have to pay their fees to reach my customers, there's no way around them. And since it's essentially impossible for a different ISP to give me a better deal to reach neighborhood X, there's no competition to bring the price down. They have a monopoly in their respective regions. Netflix might be able to take on the additional costs, as they are already a large, well-established company. But DeuceStream isn't. I'm sunk.
And that's assuming the ISPs even bother to let Netflix survive. More than likely, they'll just charge Netflix exorbitant fees to drive up the prices, making the ISP's own video streaming service inherently more competitive. If Netflix wont pony up whatever insane number the ISP chooses, their business is throttled to the point of becoming useless.
This ruling gives ISPs the ability to charge the sender and the receiver of data selectively. That's like the post office charging you to send a letter to your grandmother, charging your grandmother for receiving it, and adding an additional fee because your letter contains the word "cookies," whereas if you'd used the post office's approved words you wouldn't see the extra fee. It doesn't cost the post office more money to send the letter if you use the word cookies, they just feel like getting more money out of words they dislike. Oh, and this is in a world where FedEx and UPS literally don't exist, because there's no other organization delivering to your grandmother's neighborhood.