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.
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.
"If the gubmit can tell multinational corps not to pull oil out of the ground, they can make me hold my breath! It produces the same molecule!" Libertarian philosophy in a nutshell.