You are refusing to see the distinction between party and philosophy.
Here's the surprising thing - many people, in principle, agree with the LP or at least with major parts of it. The problem isn't the philosophy - elections in the US aren't about philosophy, they're about issues and there is a great gulf of difference between the two. Libertarians lose on the issues, not on philosophy. This is because people weight issues and the two majors tend to cover the space of issues that people actually weight heavily.