Earlier quoted context omitted.
I would agree with your argument if the broadband market were actually competitive. The author has no legitimate options for broadband besides Comcast, meaning Comcast can do essentially anything it wants to him. That is not the way a capitalist economy should work.
Actually, that is the way capitalist economies work in reality. This is a lot of crying for attention. If he wants to have a commercial use case, he should get a commercial circuit.
The key point is that the parent is stating that things ought to work a certain way. While your statement that things are a certain way may be true, it is actually a non sequitur in relation to the ought proposal.
If you wish to make a cogent argument you'll need to address the ought section of his argument or connect your "is" statement to be no longer orthogonal.