A municipality would not likely visit any violence upon a competitor, but that's largely because the only way to become a competitor (you can't just start digging holes and dropping cable in them) is through the approval of the municipality. This is where the "government-sponsored monopoly" idea comes into play, because there is often a revolving door between the government agency nominally charged with regulating cable service and the cable company that administers it.
Also, no, libertarians in general do not "believe in the concept of natural monopolies". Many libertarians hold that monopolies are short-lived and are prolonged only through the complicity of governments--or other actors which may play the same role in context, like the mafia, or even the corporation itself, should it become a de facto government. Of course, with that last point, you start begging the question...
They don't want to offer service. But they're damned sure not going to let anyone else do so -- not even let the community do so for themselves.
I'd hardly call that healthy competition.
To paraphrase P.J. O'Rourke: If you run your own cable, you'll need a permit. If you do it by negotiating with the landowners without a permit, you'll be blocked. If you do it anyway, you'll be jailed. If you try to escape from jail, you'll be shot.
Many don't, and many others only admit of very special cases. Arguments against the idea can be found with a search on "rothbard" or "mises" and "monopoly".
Thank you!
>What proof is there that this is a government created monopoly?
I'm sorry, but I thought everyone knew that in the USA, most municipalities created a monopoly right, which they sell to the highest bidder, to operate cable services within their borders. This comes up for renewal on some long term, but during that term, only the government ordained company can operate a cable service.
That's the definition of a monopoly.
>What exactly is the "violence" that Austin would do to competitors?
"Government is not reason, it is not eloquence, it is force. And like fire it can be a fearsome servant and a terrible master." -- George Washington
>Do libertarians not believe in the concept of natural monopolies?
Since most of the people who reject liberty misuse the word "monopoly" in my experience, I think you'll have to define it more precisely.
But in this case, there isn't any argument that these are natural monopolies-- like the post office, they are government created monopolies.
It is literally illegal to compete.