I think a better formulation is the so-called "platinum rule", i.e. to treat people as they want to treated (with the important qualification that you ∈ people). But even then it's not without issue (what if someone's wants are harmful to them, e.g. a child refusing to eat anything but candy?), and it's still a far cry from illuminating "objective moral principles" and fairly useless as a calculus for balancing different people's competing interests.