(1) No, this is fundamentally misunderstanding what happens when monopolistic assholes get to interact with people who are making life-or-death decisions. In those cases the monopolistic assholes always overcharge the crap out of the person who wants, more than to have more money, to be alive. You know how we keep getting news reports about why healthcare costs are higher in the US than anywhere else and it's a problem? It's invariably because there's monopolistic assholes involved -- and congrats, they just got higher due to abandoning net neutrality rules which prevent this from even being a thing.
(2) That cell phone provider was probably lying their pants off to you about the marginal cost of going from "you can use a couple apps" to "you can request the whole internet, but your bandwidth will be limited." It's very likely to be negative; you'd seem to have to build out more infrastructure to limit peoples' traffic destinations than you'd do to limit their bandwidth. (Think of the fact that Facebook is all-HTTPS these days, for example, so it's not like you're sniffing those packets without MITMing the whole connection.)
To address your earlier point, it's not really double-think. The point is, in the presence of the oligopoly the ISPs are basically Internet countries, with a strange but unelected oligarchic government at the top. We have somewhat more freedom than most to emigrate, but that's about the biggest difference. Net neutrality is an externally imposed free-trade deal among all of them. They are expressing that no, they would instead really like to charge taxes and inspect imports like makeshift customs officers, at their own anti-transparent discretion. They don't want the free-trade deal. It is indeed a valid response to say "well, tough, you're going to have this free-trade deal because the benefits of free trade for everyone in terms of innovation and public good outweigh the benefits those taxes on imports and exports will bring to your shareholders."