Because its politically popular? Gender is no more made up than any other concept of the English language.
Well...no, actually it is more made up than that. For the same reason that "key" has masculine gender in German (
Schlüssel) and feminine gender in Spanish (
llave), even though keys cannot even in principle have any gender. Just as, for example, the boundaries on what counts as "its own color" vs what is merely a
variation on some other color. English only relatively recently incorporated (invented?) the word "orange", for instance; even back in Shakespeare's day (the 1400s), they would have used "yellow-red". The very very first attested use of "orange" in English, as a color word, is from 1502, for clothing purchased for Margaret Tudor. The word had previously only been used for the fruit (or, possibly, for the county in southern France, but that only
very rarely.)
If someone started
insisting that there is no such color "orange", that's just the name of a dumb
fruit which is colored yellow-red, what would you tell them? Their color words are just as much arising from the world as yours and mine today. Likewise, why do we have different words for "orange" and "brown", but consider "navy/dark blue" and "sky/light blue" to be just tweaked versions of the same color? Orange is to brown
exactly as sky blue is to navy blue--orange is just "light brown", brown is just "dark orange". Spanish, for example, actually does give both colors distinct names:
azul is implicitly a darker blue, derived from the color of lapis lazuli, while
celeste is literally heaven-colored, hence sky blue.
Humans categorize things. We scaffold things. Its not putting them on "boxes" its making sense of the world.
It is both. That's precisely the problem. We
have to put things in boxes, to
compartmentalize, in order to process the ENORMOUS amount of information out there in the world. That's a good thing. Unfortunately, it becomes a bad thing when people treat those boxes as if they were
real. This happens all the time. That's why folks balk at the use of terms for gender, race, and other rigid categorizations of people. Because it's one thing to make wrong assumptions about a category of rocks, or stars, circuits, bubblegum, flower-parts, etc., because you reified a category that was invented by humans to attempt to simplify a complex reality. It's a
much different thing when you make wrong assumptions about a category of living, thinking
people because you reified a category that was invented by humans to simplify a complex reality.
Sex, and consequently gender, is not simple overall, for the same reason that you cannot say "math is simple"--"math" contains
whole universes of complex discourse. Sex and gender are only simple for, at best, a slight majority of the population--say maybe 60%. That's where the heterosexual, cisgender folks with typical human chromosomes and normal psychosocial development are. But then you have heterosexual people who are intersex for any of various reasons, or people who are born with an unexpected number of chromosomes (e.g. Kleinfelter syndrome is XXY), or people born with ambiguous sex organs, or...etc. And then you have homosexual or bisexual or various other preferences, and transgender persons where their socially-expected gender behavior conflicts with their lived experience, etc., etc. It gets
horrendously messy for all the edge cases--but when people reify gender as a one-size-fits-all, everyone-must-fit
requirement, rather than a best-fit
approximation full of holes and exceptions and inaccuracies, we run into problems.
And that isn't even considering how, in fantastical or science-fictional settings, we can have creatures with any biology, sociology, philosophy, and psychology we want. We can have monogender species. We can have a species where
neither the "male" nor the "female" is the one to carry the offspring, but some other situation occurs. We can have a species with three sexes, or five, or whatever. We can have a species which sees "heterosexual" and "homosexual" as bizarre uniquely human characteristics, and their perspective is
bisexual vs
monosexual (that is, the default state is that it is assumed each person is attracted to both genders, and it is considered abnormal to be attracted only to one gender, regardless of what it is--so most humans would be monosexual, but a small proportion would be bisexual and thus "normal" to this alien species.)
How did this even become a topic in a gaming thread?
It's a thread about romance. By being about romance, the probability that someone brings up a romance which is not a heterosexual cisgender female courting a heterosexual cisgender male converges to 1 as the discussion continues. Both those who want to see such representation, and those who emphatically do not want to see such representation, have plenty of reason to speak up about it--as we have seen in this and (many,
many) other threads.