Why is libertarianism so infallible?

Libertarianism is the inclusion of every sapient being into the decision making process and all that logically follows from that. Utilitarianism is the objective of ensuring the most happiness for all sapient beings and all that logically follows from that. Sometimes they compliment each other, other times they contradict.

Discuss.

>>80
What is so difficult to understand about the fact that the socialist ideal has been used profusely throughout history to justify increasing the state's power over a country?