Trans folks have had respectable roles in many societies since the days of hunting and gathering. Moreover, how many genders a culture has and what they correspond to is neither fixed nor universal. In other words, it is ancient, natural, and normal just like Asperger's or balding.

Moral criticism of trans people stems almost entirely from cultures in which the religious majority comes from an Abrahamic faith. This is ironic as none of their primary sacred texts make a moral claim regarding trans people.

Also, you have presumed that all trans people either have had or want surgery to change their bodies. This is not the case.

Keeping in mind that I approach culture and mores from an anthropological perspective, I'm glad to chat more if you like.