Yeah, I think the complexity may be the real issue. We can’t treat sex and sexual acts as if they’re handshakes. The interaction spans time and involves all kinds of (whether voluntary or involuntary) emotions and desires during that time. People are complex, and so are the emotions they feel. We simply can’t flesh out sex as some detached act of physical exercise that we can choose to divorce from its intimate nature.
I respect the desire for casual, detached sex. But I think in most cases it is unrealistic — much like a desire for a calorie-free ice cream sundae. Just because you want it, and make it clear that you want it, doesn’t mean that anyone can really give it to you.