Because there’s an explicit bias in your questioning. You wouldn’t question if I’m really cis-hetero, but you would question of I’m reeeeeeeeally gay or trans, even thought I’m sure there are more people who come up publicly as gay after having children than there are trans detransitioning.

This is the same as the maga mentality, where any man in a position of responsibility is accepted by default, but for women they demand justification for the role.