>you would expect the hiring to equally reflect both demographics
No, I wouldn't expect this at all as I do not expect the height distribution of basketball player to reflect the height distribution of the general population. As I do not expect the personality trait distribution of pop stars to be the same of programmers, and again I do not expect the latter to be similar to the general population. Personal inclination, innate intelligence, talent, conscientiousness, and of course demographics, parenting, generational wealth all play a role.
I think you wanted to say "not allowed".