Left-libertarians often think they shouldn't be A Thing, since they're extensions of state power and, besides, left-libertarians are more concerned with large concentrations of power per se than whether those concentrations happen to be called governments.

Your average common-on-the-Internet right-libertarian usually hand-waves away how they're somehow fine and part of the "natural" (I cannot roll my eyes hard enough, in case you couldn't tell) free market. Some of the softer right-libertarians (bleeding over into folks who'd likely style themselves "classical liberals" rather than libertarians) aren't as hard-line and rigid, so don't really have the dilemma to begin with, but they're much less vocal on the Internet, probably in part because they disagree with the average person a lot less than the former sort does, so it just doesn't come up as much.

Libertarians are not a hivemind. I mean, for starters, you'll have to clarify if you mean right-wing or left-wing libertarians.

Speaking for myself, as a left-wing libertarian, I think that corporations, being an artificial creation of society, can come with whatever strings society deems suitable to attach to that privilege - provided that they're the same for everyone.