Re: Common Carrier not a stretch
"the company that pipes your internet undoubtedly also sells mobile or landline phones, so would be allowed to block any competing product on their connection"
I would expect that 'internet services' would be defined (by the FCC) as NOT having this level of content blocking applied. And think about it: would YOU want YOUR company, or the company YOU invest in, to engage in THESE kinds of anti-competitive practices? Keep in mind that existing laws on the books in the USA regarding anti-trust, etc. would probably make this sort of thing illegal. As an example, you can't own the oil fields, refineries, pipelines, *AND* gasoline stations and THEN use them to control the market by inflating the wholesale prices to competing stations. Existing regulations already prevent THAT kind of abuse, something that apparently happened a LOT before Teddy Roosevelt was elected. And that's the point.
So have a little trust in the system for some common sense. Don't believe the ridiculous made-up paranoid rantings of anti-Trump'ers. De-regulation is a GOOD thing, when common sense is applied.