You write Non-Aggression Principle and voters read, "won't have our backs when we need them".
Whatever hard work Libertarians do to gain a foothold in politics is undermined by the Non-aggression principle.
I understand what you're saying. It's like people trained in martial arts avoid getting into conflict yet being ready to end conflict decisively.
While noble and proper, it's not a good selling point in the marketplace of ideas. I'm sure it resonates with some intelligent people. But the world is not exactly run by intelligent people.