There is no such thing as a "free market". What "capitalists" really want is "strong competition", not "free markets". The "free market" zealots think they are capitalists, but they really end up promoting a rentier economy where monopolists abuse state power to create perpetual advantages that benefit themselves but harm consumers in terms of higher costs, fewer options, etc.

The problem with internet services is that the infrastructure required creates a natural monopoly (ex: running fiber optic cables to each persons house), and there is a lot of regulation in many markets that ISPs are granted de facto monopoly power by the state itself in exchange for a guarantee of universal access for everyone in a given area, even if those customers are unprofitable/too expensive to service. If there was no monopoly at the ISP level, natural or otherwise, then there would be no need for net neutrality, as consumers would be able to choose alternatives and ISPs would compete on value. Net neutrality is an anti-monopolist regulation.