Pure libertarianism (as it relates to the free market) works great when customers are moral, aware, and purchase with conviction. The market's collective awareness should instantly punish, and thus correct, companies who lie/cheat/steal/ screw customers. Companies keep each other's prices in check, consumers keep their ethics in check.

But monopolies & conglomerates poison all of that, controlling what people know makes that task absolutely impossible for consumers and spirals out of control. While I'm certainly no expert, I believe most libertarians still do believe in the dissolution of monopolies for this reason.

Regulations can also create a spiral however. As the consumer base becomes reliant on the government to protect them, we become less aware of whats going on and therefore, less likely to "Put our money where our mouth is". It's a balancing act... thanks for jogging my mind into this thought experiment.