I guess, because its very hard for biological women to get abs like that. The muscles are just different. Not impossible, but way, way harder then for men and therefore quite rare.
And we all know, its very scary for bigots to even look at trans people. They might have to wash their eyes with soap now.
just wanna add that it is easier to get them with testosterone. i think it makes sense to make that distinction here since there are literal cis women body builder who take it as performance enhancing drugs.
