They try, but nobody bothers to elect them. That's why they need to pretend to be something else (like a Libertarian, a Republican, and a Constitutionalist).
Just ask Adam Kokesh. He had NO CHANCE. It was bad enough that he's an Anarcho-Barbarian, but he also thinks people of faith don't have the ability to reason or use logic and thinks he's surrounded by soulless animals.
(Here's a hint if you want to represent people. Most people don't want you taking part in any serious decision making [beyond your own life] if you think you're surrounded by stupid retards and soulless animals.)
"There are no free markets; not even for ideas."
Is there something preventing you from trying to sell your ideas (Snake oil)? Bad product sits on the shelf in a free market of ideas. Being an Anarcho-Barbarian is like being a beached whale floundering at the fringe of a sea of ideas, dying under the weight of their own blubber.
You have free speech. You just aren't capable of communicating or defending your ideas, because they're doomed to die in the light of day. Don't blame me. I tried to wave you off. I did unto you as I would hope somebody would do to me. I tried to warn you about Anarchism.
Now you're dying under the weight of 20 million you-stupid-retarded-sheeps, and you-really-are-brain-deads.