Sorry, I should rephrase. I understand ya

Nobody making these decisions cares, at the kind of scale of franchise we're talking about. If the developers care strongly about the representation of women, then that will be what decides it. Otherwise, it's simply market forces at work.
Being disappointed, mad, or otherwise making inferrals about the developers and their worldviews? The developers aren't going to care, because either it's their own politics informing their product (as it is with literally everything on the planet; everybody has political beliefs, whether they recognise them or not, and this informs the things they make as much as the arguments they partake in), or it's a business decision to maximise revenue (that the developers will have little control over).
There is absolutely no imperative for Firaxis to choose for any civ the most
successful, or most competent, or the most famous leader. (Some arguments of
leader abilities here are hilarious, similar in style and substance as to
whether Thor would beat a T. Rex in a carpark fistfight.)
Firaxis (primarily Ed Beach, I guess) will choose who they think adds texture
and interest to their game. Maybe they wanted to make a political point by
having a little known, zaftig woman leading Nubia. They are unlikely to lose
sales because of that choice (apart from some dim-witted troglodytes) and they
might actually increase interest in Civ among demographics they have identified
in their market research.
@Ferocitus
I, and most historians, ascribe Joan far more agency than any infant.
Yes, but she was far more of a symbol than an actual political leader, or
battlefield commander. There were other leaders at the same time who
were instrumental in lifting the siege of Orleans.
Those around the Court at the time would have used her as a propaganda
tool, maybe even agreeing with her decisions to take some action, but only
while it was not completely nutty. They were fully aware that the previous
king was a fruitcake, and were watching Charles VII for signs he might have
a glass jaw, limbs, and head, and body, like his father thought he had.
She led those she was allowed to lead, and she was not given free rein to
command entire armies, nor to make political decisions affecting the
nation.
She was a nine day wonder, and a fruitcake to boot.