There's really nothing wrong with sex & nudity, but a lot of this "sex & nudity" in games is done in a very tasteless or horribly juvenile & dumb manner that focuses almost exclusively on objectifying & even making sexually victimized women entertaining, instead of handling it with any kind of maturity. Sure, the same could be said for violence, but I feel objectifying women is a far larger problem in most layers of society than people going around "BOOM! Headshot!"ting other people, so it's kind of more important to get positive representation of women & their role in sex out there.
The problem with sex & nudity in games is that they are just a 5 second QTE fuck for Kratos that gives him health & experience points in God of War. You can fuck 'em & kill 'em in GTA. Grotesque (half?)naked bloody women in Bioshock. You straight up molest them in Criminal Girls. The best armor for women in some (MMO)RPGs are basically metallic bikinis which makes no sense. And DOAX just has you ogling at scantily clad women in sometimes awkward poses & situations. It's like... these games are made for men who have never seen a woman naked IRL before and get an instant hard-on with the slightest sight of side-boob or something, instead of having a more healthy approach to nudity & sex where not every (attractive) woman is immediately just an object for sexual lust.
I'm assuming this whining in the OP is because of DOAX3 not coming to the west. I think some of the criticism comes from the idea that while they've had revealing outfits in DOA games before, they default to some pretty decent looking outfits that don't objectify them too much (other than the boob jiggle) and are generally fairly capable women in a decent fighting game franchise. Even if they are virtual characters, it kind of cheapens those characters when they are put into as pandering a game as DOAX. People would probably have less of a problem with a game like if it wasn't a spin-off to an otherwise (at least somewhat) respected fighting game franchise with characters from that franchise.
While violence is a bit too easily accepted in video games (& generally), let's not pretend that it always gets a free pass. Violence is just often better contextualized (i.e. war shooters, post-apocalyptic dystopia with cannibals & ruthless scavengers) or it's against imaginary boogeymen who are out to kill you no matter what. Still, when you go totally overboard with violence with very little reason or rhyme, there are people criticizing it (i.e. killing hookers in GTA, killing totally innocent people in Postal just for fun, the violence porn that is Manhunt, even Nathan Drake killing thousands of enemies during the Uncharted games).