Yeah.... only male deers have antlers. Absurd exceptions due to hormonal malfunctions don't really count in my opinion.
This is not completely universal. Female reindeer and caribou (thought to be the same species but looking different depending on whether they live in or out of North America) can/do grow antlers.
Eora is also a fantasy setting with some fantasy species, like the stelgaer, which have "a tiger-like build, lion-like main and tail, 'sabre' teeth, and a spotted coat." Who's to say there aren't some fictional species of deer in this universe (maybe not reindeer or caribou per se) that have females with antlers?
Plus, the antlers look cool. I LOVE playing a female nature godlike who spirit-shifts into a huge antlered deer; it was my second character right out of the starting gate, after my wild orlan ranger.
Rather than getting mad about it, I just shrug and figure it's a caribou spiritshift or a fictional species of deer whose females can grow antlers, and move on.
Except that the shapeshift form is referred as a STAG, and looks like a stag.
It's a case of a person who isn't much into nature, and doesn't distinguish a female animal from a male animal, versus a person like me, who can see so obviously that the stag is a male that it ruins her immersion.