re: Is MLK's Civil Rights Act Constitutional?

You may well believe that a White supervisor should not refuse to hire a Black employee. I would agree with you.

But our agreement on the morality of that issue does not change the fact that nothing in the Constitution gives the federal government the power to control the actions of that supervisor. We either have a limited government, or we do not.

Again, however, whether a state government would have that power is a separate and distinct issue.