Yeah, funny how this happened. 
But they are,
They are what? Not a different world? Not a different time? Not a fictional version of a non U.S. affiliated military?
because the writers whether deliberate or not were based by real-life militaries when they wrote the Systems Alliance navy and the people that serve in it. Just have to face it that Mass Effect is highly influenced by contemporary western society,just as how most of character in Mass Effect are caucasian the vast majority of Generals and high ranking politcians are going to be male.
I can bring myself to face that, sure, with the stipulation that it's more influenced by Canadian culture than it is American, and that it can be highly influenced by contemporary culture while leaving the writers free to make pretty much any adjustments they please, because of the handy fact that it's a science fiction story taking place far in the future. They could have instead written a post apocalyptic story where women are back to being chattel, or they could have written a story where--due to a severe underpopulation issue--women are legally required to strive to have children every several years.
They can do anything they please, even have human culture magically locked in a state of permastasis between 2015 and 2186 CE. They didn't though, they wrote a story where gender standards have changed within the context of the universe. What OP is asking for, is that what we observe in the game matches their own lore.
Myself, personally, I'm not concerned about it. I'm trusting the Devs on this one. I think they'll probably have integrated the lore with the setting on their own.
Are people now saying prostitutes are unrealistic or something?
No, no one said that.