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 rapidly find themselves losing marketshare to competitors.

I'm not really okay with the idea of regulating net neutrality from an ideological perspective, but from a practical one, we're kind of stuck with the market we have - effective regional monopolies are granted to a very small number of companies, and there is very little space for counterbalance from competition (which is why Google Fiber is such a Huge Frickin' Deal!). Left unfettered, the end result would likely be that the AT&Ts and Comcasts end up leeching their customers dry on both ends of the pipe, because those customers don't have any alternative.

In my ideal world, there would be no need to regulate net neutrality because I could penalize bad companies by refusing to do business with them, and getting my friends and family to do the same, but we don't have those options - choosing an ISP is a lot like choosing which knee you want to be hit in. In a market where companies have been granted regulatory monopolies, the invisible hand is rather ineffective.