A person's preference of one trait over another does not necessarily mean that they have a prejudice against those that do not match them. While Nazi Germany was focused on eliminating groups of people as a form of discrimination and negative eugenics, this is not the case for someone that prefers a physical enhancement.
Humans should be given the ability to genetically alter themselves through eugenic procedures such as gene therapy. If all of human life was left up to nature, this would eliminate the use of any medical practices that prolong life. Eugenics has the possibility of eradicating certain diseases and prolonging a person's life.