Many libertarians believe that if not for government interference, monopolies wouldn't form in the free market. Those people are right in some cases (e.g. payment processing) and wrong in others (e.g. roads). But the dogmatic position asserts that it's true in all cases, and then no corporation would have sufficient coercive power so you only have to worry about the government.

If you take the practical approach and accept that there are always going to be some private monopolies and oligopolies, or even the pragmatic approach that they actually exist today and we have to deal with them today even if the wonder of the free market will eliminate them in the future, then we have to hold sufficiently coercive corporations to the same standards as governments. And at the same time try as hard as we can to destroy their coercive power, so that we can stop needing to do that.

Really, what I'm saying is that there are two ends of the continuum that look pretty obvious and which I suspect the vast majority of people would agree with, but within the continuum things get less clear are offer more room for disagreement.

Perhaps I misread this, but it sounded an awful lot like "are you on the libertarian team?"

I definitely agree that it's not black and white, especially as you delve into the corner cases.