Has nobody stopped to consider the fact that Net Neutrality (or, more appropriately, Net Neutering) more or less guarantee an eventual transition to metered pricing for customers, that metered pricing will be far more horribly abused by cablecos and telcos than any of this hypothetical preferential treatment could be, and that you'll have absolutely no recourse because the conditions will be fixed in place by regulations?
The "why" should be pretty damned obvious: you have a certain small percentage of users who consume orders of magnitude more bandwidth than others, mostly bittorrent users. ISPs deal with this in some legitimate ways like throttling (deprioritizing bittorrent packets so that they're first to drop when congestion occurs or policing the endpoints to a maximum throughput rate) and some not-so-legitimate ways (injecting connection reset packets to disrupt sessions). If you have to suddenly start treating your teenage neighbor's 8,000 pr0n torrent seeds as "equal traffic" then you either have to expand capacity by orders of magnitude to deal with it, driving up costs for everyone, or you have to introduce metered pricing (or worst case is you can just ignore it and everyone in that neighborhood has crap Internet speed). If you are worried about pricing abuse with so-called "fast lanes," that ain't nothing compared to the abuse you'll get with metered pricing.
Yes, cablecos and telcos are run by shitheads who do want to play stupid fast-lane games with their connections, but a certain amount of outrage can eventually correct that or make it livable. Getting rid of that without consequence would be desirable, but with an almost certain consequence of metered access it seems to me like people are doing an extremely poor job of picking their poisons. And for those who don't think metered access will happen haven't payed much attention to the FCC's history...
This is a practical worry about the ISPs, but it's not the worst one. The FCC is also the group of milquetoast, any-way-the-wind-blows political hacks responsible for freaking out every time there's a nipple slip on public television or somebody says a dirty word where The Children's fragile eyes and ears may be burned with hellfire. Because Satan is in boobies and f-bombs or something like that. And the only people they're semi-accountable to is Congress, who has a 9% approval rating. These are the people you want in charge of our Internet. Seriously? Yes, again, the people running telcos and cablecos are shitheads, but whenever there is hierarchy you will wind up with a shithead in charge. The only way you control these shitheads at all is by having as many as possible choose from. In this case, sorry, I think the supporters of Net Neutering have chosen their shitheads extremely poorly.