I haven't read any defenses of net neutrality that really tickle my telecom policy geek sensibilities (although plenty tickle my engineer sensibilities). Cable companies have the argument that its their private network, mostly built with private money, and Netflix, Google, etc, leverage it to reach customers. They should be able to do what they want with it. That's an almost slam-dunk argument for anyone who believes in deregulation and privatization. Their best play is to double down on the liberals. That means expanding the message. Yeah, without net neutrality cable companies could shut down startups, but that's really esoteric for your average liberal.[1] They want to hear about things like consumer protection, universal access, the digital divide, and assuring access of diverse viewpoints to media. These are people who will fight tooth and nail to keep public access stations nobody watches on the air, so figure out how to leverage those sentiments. A winning argument, if they could make it, would be: "Not having net neutrality would raise the price of everyone's Google and Facebook" or "lack of net neutrality would adversely impact rural populations" or something along those lines.

[1] I think this is where tech companies pay a price for having to awkwardly straddle the ideological divide. You come in calling for more regulation to increase competition and entrepreneurship, and people have no idea what to make of you.