There are always those hopes and dreams that always SHOULD work in theory, perhaps in a vacuum or on "Star Trek," that could never actually happen in the real world. Perhaps finding a way to kill the material desires of man or everyone being able to say the "n-word." These things will never happen because people can't ever be too rich, even if it means bankrupting everyone else. You shoulda kept me from stealing all your money, assholes! That's just how the game is played!
But that's the kind of context that Libertarians view the world through. There's no real benefit to Rand Paul's (I will not call him "Dr. Paul," because having a doctorate doesn't mean I have to show it respect) claim that businesses should be able to deny service to black people because the Civil Rights Act of 1964 improperly infringes on the rights of private citizens. How does that make the world better? It doesn't even make private business better, because even though racists would be happy, that's less money that black people are spending on shit. And everyone knows that black folks can spend some money. If not for us, the lucrative "multi-colored weave" industry wouldn't exist today.
Sure, if we were sitting in Professor Rahman's PolySci class, you might be able to make that argument, but this is the real world, where people lost lives, health, and loved ones over the central issue of whether or not the world will survive if white people have to flip the script and serve black people. Fifty years later, we can see that it didn't cause God to unleash any plagues, although if the Klan reads this, that'll suddenly become the explanation for AIDS.