Because the vast majority ARE children. Those that are not have the emotional development of teenagers. The libertarian mindset is the same mindset of every post-pubescent teenager in the world boiled down to "YOU AIN'T THE BOSS OF ME". They then wrap that into a pseudo-philosophy of thinly veiled adolescent foot stomping and temper tantrum.
So far as I can tell, their sole social agenda is the agenda of a high percentage of teens-- to do whatever drugs they want without fear of reprisal....
I hope you'll forgive me for taking exception to your gross generalization. The problem, as I see it, is that the noisy and troublesome get most of the media attention.
If I may dispute your characterization, the libertarian mindset is that the Declaration of Independence, Constitution, and Bill of Rights are to be taken seriously, rather than just being accorded lip-service. The fact that many individuals have not managed to fully comprehend the ramifications of the Freedom Philosophy, in no way indicts the philosophy, any more than Christian depravations during the Crusades indicts Christianity itself. Perhaps you would be better served to base your opinion on the words (and actions) of our more restrained and reasonable fellows, than on the unfortunate actions of a few emotional individuals.
Good assesment. Before I came to FR, I considered myself to be sympathetic to the libertarian point of view. Plenty of self-proclaimed libertarian posters cured me of that right quick!