All things are relative and people often disagree on what is sexist and what is not. That's important to remember. There is no absolute, black-and-white line.
In terms of creative freedom, all things have a right to exist. DoA Volleyball is no worse than a typical romance novel. If you don't like either one, don't play/read it. It's a simple enough solution. There should be no mandate to censor a type of game out of existence.
Traditional gaming, like it or not, is still dominated by a male demographic. More females might be more interested in it than ever but that certainly doesn't mean everything has to change. Products aimed at guys are just fine. However, the problem for me comes in when games go outside of themselves to add fan-service for no real reason. Nudity in Saint's Row is expected but imagine if Elizabeth from BioShock Infinite looked like Jessica Rabbit. That would be unnecessary, in my opinion. Skimpy armor in Dragon's Crown is something I have zero problem with but it would be ridiculous in a realistic setting.
If females really are getting into gaming then the product will expand naturally. Supply conforms to demand.
I'm still not sure why video-games take so much heat, however, when there are many other forms of media where separate products exist for men and women with little fuss.
