Some of Walter Block's greatest hits:

contract, predicated on private property [can] reach to the furthest realms of human interaction, even to voluntary slave contracts.

Otherwise, slavery wasn't so bad. You could pick cotton, sing songs, be fed nice gruel, etc.

Further, there can be no such thing as “involuntary intercourse” for the female slave whose owner is a pimp. In her slave contract, she has already agreed to alienate her body for such sexual services. Yes, it is indeed, and only, rape if her owner does not consent to this sexual intercourse. And, if the woman in question objects, which she has no right to do, ask her if she really wishes she had not made the contract in the first place, and instead allowed her child to die.

Suppose that there is a starvation situation, and the parent of the four year old child (who is not an adult) does not have enough money to keep him alive. A wealthy NAMBLA man offers this parent enough money to keep him and his family alive – if he will consent to his having sex with the child. We assume, further, that this is the only way to preserve the life of this four year old boy. Would it be criminal child abuse for the parent to accept this offer? Not on libertarian grounds. For surely it is better for the child to be a live victim of sexual abuse rather than unsullied and dead. Rather, it is the parent who consents to the death of his child, when he could have kept him alive by such extreme measures, who is the real abuser.

In a question-and-answer session, Block was asked to elaborate on his assertion that the wage disparity between blacks and whites was due to blacks being less productive than whites. In his response, Block said the "politically correct answer is that lower black productivity is due to slavery, Jim Crow legislation, poor treatment of African Americans in terms of schooling, etc. The politically incorrect explanation was supplied by Richard Herrnstein and Charles Murray in their book The Bell Curve: lower black IQs.”

Walter Block is embarrassingly popular among libertarians. He's one of the most prominent Austrian economists and anarcho-capitalists.