Keep in mind that Japan is notoriously slow to change and their right is pretty savvy about finding ways around this stuff like getting the Japanese SCOTUS to re-confirm that any tranny's who want to be legally recognized as their new mental illness must be sterilized, effectively ending that bloodline and since the last generation tended to only have 1 or 2 kids so it'll minimize the damage for a decent amount of time. Even their hard right isn't that concerned about this since Abe will likely be reelected once he's got the ulcerative colitis under control and Suga would step aside for him without question.