I find it amusing that those in favor of net neutrality consider themselves on the side of freedom.
The sticking point for me is that the market is already regulated such that it makes it very difficult for a competitor to challenge companies who engage in exploitative practices (and for similar reasons, the incentive to collude is extremely high). In a free market, net neutrality wouldn't need to be regulated because companies who attempted to enact business plans like the AT&T plan described in the article would…
An example - in Australia, there is an ISP called Internode, which used to be run by a techie called Hackett. They were very much for user's rights and net neutrality, and were always at the forefront of lobbying the government for users. Their support centers are in-country, and the web tools they offer make techies happy.
But they only have a sliver of the ISP pie, despite the very high quality product - because that shit does not come cheap. They're 50-100% more expensive. Instead the public run towards big brands like Optus - who actively engage in tactics like obscuring the structure of your bill to make it harder to understand, or engage in openly deceptive marketing, and see users as cattle to manipulate. Or they'll go to bargain-basement ISPs with woeful service, then complain about that service and give you a hateful stare when you suggest they pay a little more for good service.
I can see zero evidence to suggest that 'net neutrality' is a killer feature that would be automatically enabled by a free market.