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.

Its not infallible, its unfalsifiable, meaning that there is no way to prove it wrong. Other unfalsifiables are if there is a god or if there is alien reptiles living among us in neat flesh suits.