Why is it so terrible for a guy to reject a fat girl, but it's okay for a girl to reject a guy losing his hair?

90% of females under 24 will not consider dating a guy losing his hair/going bald. I knew a guy that started losing his hair at SIXTEEN and girls didn't give him the time of day in HS or college. You can control being fat--both of my parents are obese, and I'm 6'3" with a 31" waist. You can't help but lose your hair if genetically pre-programmed to do so. My hair is also receding, and became noticeable my senior year of college.