How can libertarians be so cynical about government yet so naive about the free market?

[I love everyone]

Libertarians will hardly acknowledge the possibility that government can do things which are beneficial to society, even when they look at positive outcomes from things like social security they will turn around and argue that it's actually a negative outcome in disguise. Yet when it comes to the free market they have unshakable faith in it, like they just trust that everyone who is pursuing profit will automatically do what is best for society, because it's bad PR to do otherwise. They seem to be unaware of the possibility that the pursuit of profit and what is best for society often creates a conflict of interest.
I don't automatically trust government. I look at things like social security and think "ok that works" and I look at things like the patriot act and think "ok that doesn't work". Quality of government over quantity of government.
SS is so easy to fix!! Get rid of the $100,000 cap on SS taxable income. Problem solved. Right now it is funded by an obscenely regressive tax system, it's funded entirely by the working class.