So you're just going to pretend that the female chest is seen as so much more sexualized than the male one? Because that's the exact reason why no one raises a fuss when men fight shirtless. Sure, man-chest can be pretty damn sexy, but it's not as sexual as bare breasts.
If female Qunari fought in their armies, and all Qunari fought shirtless, I'd imagine that they would fit right in. So long as there wasn't any extra effort put in to making the female warriors sexy beyond what being shirtless provided, I wouldn't have a problem with it. No arched backs, crawling on the ground, erotic moans, or "come hither" looks? All good then. Give her [http://img1.wikia.nocookie.net/__cb20130902021109/dragonage/images/e/e3/Qunari_DA2.png] a bit more muscle and you've got a shirtless warrior woman fighting and a shirtless warrior man (granted, with censoring straps).
The problem with your example though, is that you only have the males to look at for the Qunari warrior's outfit. I haven't played DA2, but maybe the Qunari don't like armor? Maybe they think it's weak, or covers their warpaint or is against their religion, or whatever. The thing is, an entire culture that is still pretty unknown fighting shirtless does not violate the world's consistency.
If the Qunari did wear armor (and the women fought) and the males got realistic armor while the women had boobplates and midriffs exposed, that would violate internal consistency, because "culture" can't just be assumed to cover your standard, sexualized armor the way it can for "they all fight without armor."