The old "people won't buy stuff from companies that are dicking them over or killing the envionrment", always conveniently ignores the fact that if one company is behaving badly but getting better profits (exploiting their workers for short term gain, dumping toxic waste into the rivers, etc...), they will ultimately consume any well behaved competitors.
Unfettered markets are pure dog eat dog territory, and frivolities like environmental protection and human rights do not survive. We know what unregulated markets look like, they are cities filled with factories churning out toxic smoke, hospitals full of terminal cancer cases, people dying on the street, and everything else you read about in the Industrial Age. Or go to any factory city in China. They're making tons of shareholder profit and they're dying at the same time.
Libertarians are the worst at not fully thinking through the ramifications of their positions.