Net neutrality? Doesn't really exist...
Traffic management is needed. That is a given until we find a way to simultaneously transmit infinite amounts of data at infinite speeds between all the different points in the world that should need them and for free.
As all those conditions are unlikely to be happening anytime soon, this means that there is a cost involved in putting in network infrastructure, and although the more bandwidth you put in makes things cheaper on a per-bit basis, there are limits to how much infrastructure companies are willing to put in.
Let's not forget that transporting data is a business. Service providers want to recover their investments in a timely manner and see a worthwhile return on that investment (ie that the cash put in makes a profit when factoring risks, amortization, maintenance, etc....).
So... limited infrastructure based on cost and/or business model, which will be (presumably) less than the potential demand for bandwidth.
If service provider "A" has a flat fee schedule where all of its customers pay the same amount and bandwidth gets shared around on some sort of equal footing (erm.... should we put in traffic management to make sure that the customers get the same amount, or should the customer that is hammering the network more get more? hmmm.... already the notion of traffic management cropping up.....), and along comes someone (a rich individual or a company) who says "look, that amount of bandwidth at that service level is not good enough for me, can you give me more if I pay more?", I really don't see the issue about it.
Also, either due to a business opportunity, or due to excess stress on the network, a provider may choose to limit a certain type of traffic (either throttle it or block it) unless there is a payment involved.
Note that we are no longer in a telco monopoly situation (in most developed countries at least... the issue of monopolistic situations is a completely different one), and thus if a certain service provider is doing things that some people consider unacceptable ("OMG, I can't get to site www.joeblogs unless I pay them $$$$!!!" or "Crap, as www.joeblogs doesn't pay the provider, I can't see them"), then move over to another provider that acts in a more acceptable way.
The argument of "I want unlimited access to everywhere for free (or at a price that *I* decide) is just not going to happen.
Alternatively, if you (and enough like you) are convinced that there is a valid business model in giving out unlimited access at unlimited speeds to everyone (and stating in a contract that you ARE giving unlimited speed/volume), then write up the business case and seek funding for your wonderful new service provider... I'm sure you will make loads of cash...