Because some of us want the real thing, not the fake thing achieved by cheaters.
I'm the same in other areas of life. I don't take steroids, I work out in the gym. I don't take drugs to have trips and achieve enlightenment, I tried to find Zen on my own.
I wouldn't partner with someone who had a cosmetic surgery ("fake beauty"), nor someone who wears makeup.
Up to every individual of course, I'm not even saying I will never take TRT (probably eventually, when I'm older, for health reasons), but I, above everything else, value (and want) authenticity.