True libertarians do not believe in Adam Smith's philosophy. At most it's a baby step in the right direction.
We follow the philosophy of people like von Mises or Murray Rothbard: every individual has a right to his life, liberty, and everything derived from it (e.g. his income and property) and as long as he does not interfere with the rights of others, he should be free to act in his own self interest.
The modern corporate state is anathema to this view. We are Jeffersonians, and the ruling elite (of both major parties--which most libertarians don't consider to be any different) are Hamiltonians. We have these mega-corps, because the politicians and bureaucrats are in the pockets of big business, and no matter how campaign financing gets reformed, they always will be, as long as they have the power to write and enforce laws. The regulations in place to "protect the consumers" are designed by the big companies to eliminate the competition. Why does Wal-Mart want to increase minimum wage? Because they believe in a glorious society where everyone is wealthy? Or because they can afford it, while the mom-n-pops that they haven't yet killed off, who are barely scraping by, can't afford it?
Big, bloated, inefficient government leads to big, bloated, inefficient corps, with no real innovation or market competition.
I don't know a single true libertarian who has any issue with open source; ESR is well known as a libertarian. Many of us do have issues with RMS and his line of thinking. In addition to being an admitted socialist, he has implied, if not outright stated, that he would like to use force to make all software free as in speech. Libertarianism says that the owners of software should decide how to release it, and the market (i.e. we, the customers) should decide with our dollars whether to support them or not.
Libertarians oppose "net neutrality" because there's nothing neutral about it. It's some group forcing what it thinks is right onto others. If Commcast wants to start charging you more every time you request a page from Google, let them. Do you think people will be more loyal to Commcast and stop using Google, or more loyal to Google and ditch Commcast? If you live someplace where you're stuck with a single cable company or phone company due to a government granted monopoly (more regulation screwing the customers for the benefit of a corp) or a very rural residence, then you might get screwed. But as technology advances (and regulations disappear), we'll have dozens of choices for net access, and the marketplace will act to reduce prices, as it does in all other fields.
The other, and more insidious, downside to "net neutrality" is where it will lead. Governments never shrink willingly, they only grow. The income tax, which was never supposed to exceed 1% or affect anyone other than a few hundred super-rich, now takes a third of the average American's earnings. Interstate commerce, which at one point meant goods shipped across state lines for sale in another state, now includes customers at a restaurant (they could be from out of state, after all), ducks (the do migrate across state lines), and even marijuana grown in California and sold in California to residents of California (the sale of local grown goods reduces the need for imports, affecting interstate commerce). Does anyone honestly expect the Feds not to follow up net neutrality with a powergrab for more? Federal online sales tax anyone? Federal licensing for "broadcasting" a website or blog? Federal control of what you can say on a blog about politics? Federal regulations on encryption, requiring a backdoor, so they can monitor everything? And how about, complete government control over the entire internet? It is an "essential service" like roads, or health care, much too important to be left to the whim of the free market. Sounds lovely, doesn't it?
Most so called libertarian think tanks, like Cato, have been corrupted by the corporatists (i.e. Republi-crats) and shill for big business. Even the Libertarian Party (capital-L is the party, lowercase-l is the philosophy) has started to turn into a beltway insider group