What if your biggest regret in life was a birth defect that defined your bloodline? What if you spent most of your time regretting a 'thin blood'? What if you could never afford to have a decent drink in your entire life, because it would kill you? I bet your definitions of morality would become pretty warped.
Because you are not one of those people, you can't imagine what life would be like for one of them? I am not predisposed upon the limitations towards imagination.