Amethysta I agree with you, there is no linear answer to why we are transgender. Believe me for five years I have exhaustively searched, like many transgender people, for that answer.
I now simply lead with "I just am."
Society is waiting for science and the creation of words and language to answer what is "gender" and "where does it come from"? It will take time but it will come. Society does evolve but very slowly, just ask Galileo, Darwin and Dr. Martin Luther King. We just need to keep the pressure on to make sure it happens.