I'll tell you why people as a whole are more "offended" at displays of sexuality than violence. Sexuality is more of a personal issue that effect us almost everyday of our lives as we interact with people. Now, there are some pretty violent people out there, but I would like to think that the mass majority of us have no intentions of blowing up cars or stabbing someone in the gut until their insides all fall out. I hope you get the picture here. But we as living beings react to stimuli. It's just how we are, and we need to moderate that reaction as we interact with others.
There are a number of reasons why someone takes "offense" when sexuality is displayed in most any media (such as video games). Usually, it's a defense mechanism in which seeing something sexual triggers a sexual response within that person. Depending how personal an individual views sexuality normally determines how "offended" a person gets. In general, let's put it like this: When something make you happy, you smile. When something goes wrong, we get frustrated. More specifically when something sexually arouses you, you get turned on. And then it's how you hand that reaction. It's understandable why someone would feel "embarrassed" when they see a display of sexuality in a video game. It's a reaction that being triggered that's more personal to them than others that they would prefer to keep private. And it SHOULD BE RESPECTED.
Then there are those who live by the "letter of the law." Those people just don't have a clue. They are the pharisaical types, and that's for another discussion.
I don't need sexuality and/or violence in video games to enjoy it. But I'm also not avoiding it. What I see on the tv screen when playing a game is fiction and purely fiction. In real life, I condemn both sexuality and violence when abused. But I accept violence while also greiving the use of it as a last resort. That is as far as I'll go because my view of sexuality will trigger I suspect a plethora of INTOLERANT responses, ironically very similar to those who "knee-jerk" reactively respond to sexuality in video games.