Actually the “last mile” is almost never a monopoly. In most urban and suburban areas, both the landline phone company and the cable company offer internet access. There are usually two or three cell companies that cover such areas as well.
For those wanting higher bandwidth, there are other options, admittedly more expensive.
And, most ISP’s who suppress content do so under threats of lawsuits or harassment. This is a separate issue, that should certainly be addressed at the national legislative level, with the FCC then responsible for technical implementation.
I’ll agree that in more rural areas, where there’s only one provider, local regulatory bodies (and perhaps courts) should be available to oversee the 1st Amendment rights of customers. But regulators, either local or national, are actually the greatest threat to freedom of information (note the date on that linked article).