The "invisible hand" that they cherish so much only works in certain market conditions.
Which is why we have been trying for decades to create those market conditions.
Conditions that any self respecting corporation will seek to prevent as soon as they gain enough power.
From the libertarian viewpoint, these groups are fairly easy to defeat. Take away their assets and they're no longer a self respecting corporation. These businesses have hard assets that are hard to hide or move. They cause this sort of trouble, then break or take their assets (libertarians allow for such force in response to coercion). All these "company towns" require extensive collusion with state and local (sometimes federal) governments in order to protect the assets of the business in question. Historically, that was taken away by labor law and anti-competitive regulation, but in a libertarian society, the business no longer has that powerful ally to protect it while it engages in harmful activities.
I think a greater weakness of the libertarian viewpoint is simply that people historically choose safety over freedom. One needs social infrastructure that supports the libertarian strategy, eg, choosing to take on a tyrant, oppressive business, or crime lord and doing so in an organized way. This infrastructure simply doesn't exist in most of the world.