This question came to me when I was designing the culture of a fictional country. I was wondering outside of the life sciences, why do we use gender, and should we keep it in our daily lives. In my own view the division of people by physical gender is pointless and serves only to create conflict.
Foot race or motorsport race?
Race to me is another thing I can't conform to because I am made up by a diversity of several ethnicities. I find putting people into segregated groups by skin colour and ethnicity is stupid.
Being of mixed heritage, I am rather confounded by the concept of racism - but I am still aware that I am of mixed heritage and know the race of both my mother and father; a concept that is confirmed by society recognizing their races as well. To try to deny that race exists not only erases their cultural identities, but erases my identity as well since my self perception has been significantly shaped by knowing I wasn't fully accepted in either culture. Hmmm, this is starting to sound a lot like your experience with gender.
That reality doesn't promote anything. It just is. That's like saying that black and white promote a desire for colors. They're just opposite shades that exist with or without our consent. Wringing your hands over their existence doesn't make them turn blue, red, yellow, or any shade of gray. Accept and embrace this, because it's the only reality there is, regarding this topic. The fact that the cause & effect of this reality has some egregious consequences, in your eyes, shouldn't blind you from all the great things that do come out of our reproductive system, and our undeniable gender differences, the semantics of which word to use notwithstanding.
But what wonderful conflict.
Anyway, you seem to be making an assumption that conflict is bad. In a dialectical realilty, conflict is part of the engine that results in all sorts of improvements.
Sexual reproduction allows our species (and others) to evolve more quickly in response to environmental changes. Gender is the reflection of the importance of reproduction in our lives and for our society. At its most base gender may be about reproduction and allowing the species to evolve, but the individual fates of members of our species (and their offspring) can be dramatically effected by their choice of mates. Gender is essentially the first issue or step if you will in our very complicated and vitally important mating rituals.
And beyond all that, how does natural selection explain the emergence of gender? While I believe in evolution wholeheartedly, I grant that it doesn't explain everything, or perhaps better: it doesn't always provide us with obvious, easily understood, prepackaged explanations.
How does natural selection create the two sexes, which can't reproduce without each other, in parallel and timed correctly so that heterosexuality can begin? And was there a period during which an early species existed in both heterosexual and unisexual forms, with heterosexuality finally prevailing.
It's hard to imagine how some creatures living and some creatures dying due to survivability resulted in heterosexuality, especially since it has a distinct disadvantage against unisexuality when it comes to moving the species forward and ensuring its survival, which is that if I'm a unisexual creature, I don't need to find a mate, I can just produce clones of myself. Unisexual creatures have demonstrated survivability. they are very ancient and all around us.
It's a puzzle to which we may never know the answer.
BTW, search on "how does evolution explain heterosexuality?" in google and notice that all the main answers have thE original question changed around to a totally different and unrelated question. All those first answers are about "how does evolution explain HOMOSEXUALITY?"!!!
Go ask and evolutionary biologist.