The full answer, which is boring as hell, doesn't prove your position - and in my opinion - is a waste of time (and I kind already stated above in other words):

Original societal concepts of what a "woman" is come from biological sex. No doubt about that. What what many consider gender now isn't the same as that.

Same as marriage isn't some natural phenomena. Society isn't really "natural" either.

If someone FEELS like they are a woman, then they are to me, what more do we really NEED to define it as? What purpose can it possibly serve?

The concept of a "woman" is still vaguely based on historical ideas of what a woman is - but what a woman is isn't some fixed concept. Women used to be seen like second class citizens without the right to vote, who should stay at home, and obey their husbands. That was what some cultures defined as being a woman.

No one's forcing you to be attracted to a woman who was male at birth. Literally how does this affect you or anyone else?

Christ, identity politics is such a waste of time. Why do you give a shit what equipment people have in their pants? It's weird.