nigel, that would be a libertarian basis of support for laws banning private discrimination. My position really is not that much different.
I don't agree with discrimination to exclude minorities. I don't have a problem with minorities discriminating to avoid being overwhelmed by the will of the majority (e.g., minority beauty pageants). The intentions and the effects are quite different.
Though, I don't fully support laws banning private discrimination even to exclude minorities, I won't support it or refrain from denouncing it. It's wrong, but just because it is wrong does not mean it should be illegal.
I am confident that most Americans agree with me that private discrimination to exclude minorities is wrong and would punish it in the market. If they did not agree, the CRA would never have passed or would have been overturned or repealed by now. That's part of the reason why I would not make an issue of it because some racist might get the wrong idea and think I am on his side or someone like you, who I am probably far closer to on the morality of discrimination, might assume the same.
You can say it is some sort of closet racism if you want. nAHZi and the other mouth-breathing knuckle-draggers already call me racist. Go ahead and join them if you want (not implying you are... you seem to be giving it a fair hearing). But, you will be wrong.
No, I'm not saying you're racist. But I don't think libertarian ideals compel the conclusion that, to the extent that the CRA prohibited private businesses from discriminating on the basis of race, it violates libertarian principles.