Moral Laws and Invention of Mankind for the Disenfranchisement of the Strong

According to Kant, that's because we are in a way following laws issued from within. The judge will explicitly reject this in the another passage just after the one we read. But going further, historical loss subverts it at every turn. A moral view can never be proven right or wrong by any ultimate test. That is not the path to autonomy. It's never going to give you a final proof of anything.