Because that leads to seperation which leads to discrimination. That would be like saying “black people should have their own sports competitions seprate from white people bc if an imaginary increase in skill that on average may affect some people.” That sounds insane, but why do you only care when trans people are involved?
Well, the fact that gender is LITERALLY DETERMINED THROUGH MASCULINIZATION OF THE BRAIN IN THE FIRST TI MONTHS OF PREGNANCY also doesnt lie. Read this study BY THE US MEDICAL SYSTEM. https://pubmed.ncbi.nlm.nih.gov/17875490/
