This is the correct answer. Literally every argument against Net Neutrality I've heard/read was based largely in the person making it's ignorance of what Net Neutrality even is.
Here's the only decent argument.
Right now, there are certain internet applications that are impossible due to lack of bandwidth. Maybe the only obvious one is streaming HD video across wireless networks. So, you can't get an HD video conference on your Ipad when you're on the train. If you could prioritize that kind of traffic across the internet, you might be able to boost the speed enough to allow new applications.
The problem with that argument is that 10 years ago you couldn't stream audio on your wireless device. And, now you can. Bandwidth seems to basically keep pace with the web applications we want. How often do you say, my internet speed is too slow to do "XYZ?" For me, it's somewhere around never. When I'm on the go, I don't really want to use high-bandwith applications. I don't want to stream a full HD movie on my phone while I'm on the bus. When I'm at home, my home wifi is as fast enough for streaming netflix. The market is not screaming out for an end to net neutrality.
So, why does Comcast hate net neutrality? They want to use their market power to extract economic rents. They want to bully google, Netflix and such into giving them money. They want to turn an efficient and open market into the most profitable market for Comcast. That would be bad for consumers, bad for the economy, bad for content creators, bad for new startups and innovators, and good for the big players in the broadband market.