I am a staunch thin or pure libertarian. For me, the correct (Rothbardian) libertarianism is firmly predicated on the non aggression principle (NAP): the law should prohibit the initiation of violence against innocent people and their property. That is it. That is entirely it. There is no more to thin libertarianism, other than implications of this basic axiom; well, thats quite a lot.
Of late however, many leftists have been attempting to hijack the good ship libertarian in their own direction, adding to the NAP their own pet projects: opposition to bossism, racism, sexism, homophobia, prejudice, bigotry, brutalism, etc. Some call this humanitarian libertarianism, many call it thick libertarianism, and others characterize this as "New Libertarianism"