Black people are among the poorest in the country. One can try to explain this away with racial pseudo science which proclaims this economic disparity is due to an inherent racial flaw as people like Rothbard and Rockwell have, or you can acknowledge that it is an instance of racial hegemony perpetuated by the institution of private property which grants a legal entitlement to the value created from productive labor to property owners. You see, when one group of people is descended from the owning class which has reaped the benefit of the institution of private property for hundreds of years, and another is descended from people who were property themselves, you cannot simply expect to wave magic free market wand and pretend that individuals and their material conditions result from their own merit and abilities. Quite simply put, when poor black people and other people of color look at the principles of US libertarianism, they see the new boss the same as the old boss. They see a system that perpetuates their material conditions based on hundreds of years of the accumulation of wealth through slavery, genocide, and white supremacy through the social enforcement of private property rights.
Pro-capitalist libertarianism is inherently more beneficial to those in society who have a greater access to capital, and that happens to be white men. You can’t expect people with the least amount of property and wealth to want to sign up to be the underclass in a propertarian utopia where access to property and capital directly grant one greater social mobility and privilege. It doesn’t take a political science major or economist to figure this out.