Why libertarian?

Because prohibition, time and again in multiple places and locations, has been shown to not merely fail in it's goal as a strategy (frequently the banned commodity is MORE in demand/available than when the fun began), but to create nasty black markets with regrettably violent conflict resolution techniques.

Because it's none of my (or anyone elses) business which consenting adults engage in recreational lechery together.

Because anything an individual can screw up, a group of individuals with the might of government behind them can screw up on a far grander scale. Groups are seldom brighter than the dimmest member of the group, merely having more resources with which to act badly.

Because religion and government are both mutually toxic and tend to splatter.

Because freedom of speech, thought, the press, etc are important.

Because privacy is important, regardless of the whimsy of the day.

Because despite noble intentions to the contrary, surviving the two-legged critters and life generally with minimal damage comes down to individual responsibility 90% of the time - and I don't like folks that would limit my tool set.

Because I can spend my own money, thank you very much. Why, I can even choose the charities I want to support.

A partial list, but on a pre-brunch Sunday morning ...