Federal Communications Commission Chairman Ajit Pai has consistently argued that FCC regulation of net neutrality is "a solution in search of a problem."
Pai's claim is frequently countered with the actual history of Internet service providers blocking or throttling Internet traffic or applications. The most prominent example is Comcast's throttling of BitTorrent peer-to-peer file sharing. Pai thus had to contend with these real-world examples in his new proposal to eliminate net neutrality rules.
Pai's solution has been to argue that these blocking and throttling incidents stopped after public pressure, that they haven't happened much since, and likely won't happen again. Of course, the most obvious reason that net neutrality violations have been rare since the Comcast/BitTorrent kerfuffle is that the FCC has enforced net neutrality rules since 2010 (aside from a year-long interlude without rules caused by a Verizon lawsuit).