It gets respect because the wealthy elite benefit from its policies being put into place, and they control the narrative/policy. They whip up the populace into a frenzy about 'freedom', invent/purchase 'grassroots' organizations like the tea party, etc. The ideas don't stand on their own merits without a lot of self-interested wealth propping them up. Which is why libertarianism generally gets laughed out of academic circles; critical analysis without a profit motive generally exposes it for what it is, a method for siphoning wealth from the poor to the rich.