I understand how it can seem progressive to assert that “gender” or “sexuality” are personal or private matters that are “none of anyone else’s business” but this ignores the fact that both gender and sexuality are social phenomena, not just personal traits or characteristics. Both are delineated and reinforced through a variety of social institutions and cultural practices including law, politics, religion, education, the military, the workplace, fine art/literature and the mass media. You really only have to look at how clothing is organized at Target or Wal-Mart to see how gender norms are reinforced by social practices such as retail merchandising under Late Capitalism, etc. Other examples are endless.
Claiming that gender or sexuality is solely a private matter might appear a magnanimous gesture of respect for individual rights, but it really only serves to obscure the true character of gender and hinder thoughtful analysis by blinding us to its reality. By which I mean: it’s reactionary Libertarian B.S. If you’re interested in better understanding the social dimensions of gender, you could do worse that Judith Lorber’s famous book The Paradoxes of Gender (Yale University Press, 1992). The key chapter (“Night to His Day: The Social Construction of Gender”) is widely excerpted in .pdf form on the internet.
Finally, no, identity is not a “choice.” No, we’re not all free to express ourselves any way we “choose.” All those expectant parents YouTubing their gender-reveal parties would be surprised to learn that “gender no longer exists.” And, gender is about a great deal more than biological sex (what’s “between your legs”) and sexual behavior (who you are “banging.”)
The rest of your response is about….other things, so I’ll refrain from commenting.