Net neutrality isn't as simple as issue as the 'feel good' moniker would suggest. You have to have an awareness for the current byzantine morass of legislation that has accrued, how legal precedents work, and strict limits on federal powers defined in the constitution. Seen in the historical context, Dr. Paul is opposed to further expansion of legislative competencies, and he is *adamant* about not allowing government to regulate content on the internet.
Laws regulating how ISPs treat content, if upheld in the SCOTUS can become a wedge for introducing more legislation that regulates the market in even more distorting and freedom-limiting ways. While the idea, (and particularly the label) of 'Net Neutrality' is appealing at first glance, it has a legislative 'pandoras box' aspect, which is cause for some concern.
Dr. Paul represents the limited government philosophy that market competition - allowing consumer choice, is generally a safer guarantor that service providers will give consumers what they want. However the fact that many regions of the USA are not served by a large number of ISPs means that in some areas the service provider market resembles an oligarchy more than a market, and they take on part of the character of a public infrastructure.
Weighing these factors against one another reveals this to be a problem of legitimate conflicts of interests, and enacting legislation on them at this (historically) early part of the life of the internet would have long-lasting consequences. Our current government is too quick to pass laws addressing percieved or real problems, often in unreflected haste. Consider that most legislators do not read through most of the bills passed in congress, and you get a sense at how irresponsible and cancerous lawmaking is today.