Not much of a revelation, just an observation, but how much of sci-fi pushes the ideal that Humanity's path forward is unification?
Star Trek is a major one, and many would state it was a progressive show, and it earnestly was.
It also stated that in its ideal future, there's a Federation of like-minded extraterrestrials, and as a member species, Humanity lives in a united, post-scarcity society under a single government.
To that end, how many alien species in these stories are so inhuman, in that they have no differences, a world-wide government, a single language?
It's laughable how direct the propaganda was, and continues to be.
The thing is, they're conflating "male" with "masculine", and the two are NOT THE SAME (though the latter is based on the former, of course).
Think of Namekians - they "present" as masculine. Deep voices, male-ish body shape. But they're kind of reptilian-looking, and they reproduce asexually, by sporing an egg out of their mouths (and can even control the traits of the offspring within, apparently.) So they're not male. They're asexual "its". But it's just polite to refer to them in the masculine, as if they were male.
Moclans are similar, somehow, but still mate sexually. Maybe like snails, but without impregnating each other at the same time. They're masculine, but not "male". The "feminine" variant is likely just that. Can they breed with each other, like the masculines? Can masculines and feminines interbreed? If the latter is not true, but the former is, then they're DIFFERENT SPECIES.
There's a European crustacean that spawned an asexual species about 25 years ago or so. One day, a double-X with the ability to clone itself was born, but this creature - and its clones - can't breed with its own father (or creatures like its father.) So, different species.