Why is libertarianism so infallible?

It is due to it being the application of political science. It does not permit failed policies to be continued fruitlessly year after year with idealistic fervour, it is next to impossible for anyone surrounded by fierce libertarian critics to continue clinging on to lies. It is a purely functional machine, lubricated with justice and fueled by free speech.

Just an aside: vigilante justice is mixed news.

You're obviously not just advocating self-defence, because you would go and help a Kitty Genovese, right? Right?

Now multiply that by another dozen people with good intentions.

PS. for those who don't get it: you hear a scream, you rush out with your gun. You see another person with a gun. Whadda ya do?

Now ask yourself if everyone will behave responsibly in the heat of the situation.