For example historically slave-owners still desired...
Universal individual desires
Certain desires, such as the desire for happiness, are universal to all human beings. Even if they actively deny them to others, every individual works towards the fulfilment of these desires for himself, and recognise that the denial of this fulfilment is harmful to himself. For example historically slave-owners still desired freedom of movement and labour for themselves, even if they denied it to their slaves on the basis of selfish interests. Therefore, because all humans desire happiness for themselves, and also desire the means to this end such as freedom of speech and the freedom to make their own choices, there exists a universal basis of desire for human rights in every individual. The enshrinement of 'fundamental human rights' simply universalizes what every individual acknowledges for himself: that the denial of certain rights is always harmful. This already even has a basis in the 'Golden Rule', to not do what is harmful to yourself to others, which can be found in some form in almost every ethical tradition.[1] [1] Blackburn, Simon. “Ethics: A Very Short Introduction”. Oxford: Oxford University Press. 2001. p.101