This also reminds me of the SCOTUS decision last year that lifted regulations that aimed at limiting states from implementing election laws that discriminated against minorities because SCOTUS deemed that this problem has been solved and there's no discrimination anymore. Just several days after, 5-6 states had filed for passing discriminatory laws to prohibit huge chunks of their citizenry from voting.
The belief that we don't need those laws anymore is demonstrably false on other levels as well. Even in current society blacks are being discriminated against, both from government officials and from private businesses and it has resulted in huge discrepancies in the way they are treated and the end results of it - less job opportunities, higher poverty levels, less education, higher crime rates, higher incarceration rates, etc. All of those are traceable back to discrimination by businesses and by officials. It fuels the vicious circle. I will give you an example - there was a study that was made in Chicago and Boston areas(I don't have it right now, if you demand to check it out, I'd have to search for it). The researcher sent resumes to thousands of companies that have announced job openings. The key was she sent resumes with equivalent qualifications and skills, but with different names(black sounding names vs white sounding names). The result was that the fictitious people with black sounding names got 50% less calls for interviews. Interestingly enough the study showed no statistical difference of significance between the number of calls men and women got. There was another similar research showing that black people with criminal record have less chance of getting a job than white people with criminal record. The fact that this discrimination is to a huge degree hidden doesn't mean that it's not happening and it's not problematic.
This libertarian idea is one of the few that has actually been tested and has been demonstrated to not work time and time again. Whenever discrimination has been allowed, it has been implemented and it has lead to horrible problems and results both to the society and to the people discriminated against.