Technology

Let me give you an analogy.

I was born in the People's Republic of China. I immigrated to the United States of America when I was not even 10. I grew up in America, I grew attached to the principles of Freedom and Democracy. I went through the proper channels and I obtained Citizenship through the proper way. I am an American.

If someone were to tell me that I'm "not American", and that because I was "born Chinese, I must be Chinese for the rest of my life"; or, in your phrasing: "A Chinese person cannot become American" you'd be a xenophobe.

Gender is a social contruct. If a man wants to be a woman, or a woman wants to be a man, just let them. Its not denying that they have XX or XY chromosomes, that is what their biology says. But being a "Man" or "Woman" are labels society attributes to those chromosomes, just like the concept of Nationality.

TLDR: Please just let people be whoever they want to be. If you start attacking people's identity, nobody is gonna wanna talk to you. If you want to spread transphobia, you can go to twitter. Enjoy your nazi bar.