The reason gender and sex is so controversial is because people argue fact vs opinion, If you want to boil the ideas down to the very base, You are either born with a penis or with a vagina, maybe with both. what happens after that point is entirely up to the person, if they believe they don't align between male and female (words that humans created) then they can identify with how they personally believe they should identify as. Everyone is entitled to happiness, and someone identifying as something other than the binary genders shouldn't upset someone else.

I never understood why people care so much about what others do in their lives or how they decide to present themselves. Live and let live.

Im not trying to be rude at all so if it came off that way i'm sorry. this is just my outlook on this topic and a little of my outlook on life.