I don't agree that liberal rights somehow "contain" totalitarianism. Some of Frankfurters used to talk like that too, but I think it's idealism. Anyway, liberal rights are not the be all and end all; it's just that we have found nothing better so far.
Whether capitalism required Judaeo-Christianity, who knows. I have always been suspicious of the Weber thesis.
I agree that Marxism is not a universal science of s, but I am not sure that I would go as afar as Korsch in saying that it is only a science of bourgeois society.
--jks