The Advocates' quiz has never asked a question about "peace" in its entire history.
It's not been my experience that young liberals aren't committed to their collectivist economics. Alex Peak tried to make the same point when he wrote here a couple weeks ago that liberals "only ever start supporting government control over the economy because (A) they are convinced that a person who opposes homosexuality must also be wrong about everything else, including economics; and (B) because the democratic socialists seem (and usually generally are) genuinely concerned about people’s well-being".
But if this thesis were true, then recruiting Libertarians from the left would be as easy as letting them know that the LP exists and that we care about people. Mary Ruwart would be leading an army of ex-liberals into the LP. So where are they?
I don't buy the theory that it's "because we have positioned ourselves so as to be more welcoming to disgruntled older conservatives". When I've promoted the LP's free-market economics to liberals, I don't recall ever hearing a complaint that the LP is too closely tied to old men like Ron Paul or Bob Barr who are proud of the "conservative" label. Instead, the pushback I hear is that libertarians are against government provision of even basic services like streets and police, and believe that markets can regulate themselves against fraud without any government help.
I wonder where they got that idea?
The strawman of anarcholibertarianism is the scarecrow that leftist shepherds use to keep their flock out of the LP's greener pastures.
Note that Ron Paul is explicitly a constitutionalist, and explicitly not an anarchist. In Lew Rockwell's speech at the Campaign For Liberty convention in 2008, Rockwell didn't give the slightest hint of his anarchism. I'm confident not a single speaker there advocated anarchism. The C4L blog editor Anthony Gregory is an anarchist, but you don't see him advocating anarchism anywhere on the C4L site. Ron Paul and the C4L are indeed a good example of how appealing minarchist libertarianism can be when it's not so easy to dismiss as mere anarchism.
Constitutionalism is indeed a meme the LP should be surfing, but there is an even bigger wave we need to catch. California is still a leading indicator for America, and as the father of three young Californians I can report that our government schools are shamelessly mass-producing young environmental activists. If American freedom has a future, that future will have to be green. Pollution is aggression, and libertarian economists and think tanks are nearly unanimous in supporting Pigovian taxes on such negative externalities, but the LP's position on the environment is held hostage by those who deny the State's authority to tax aggression. Green-/Eco-/Geo-libertarianism is the answer, if the LP can just bring itself to ask the question.