I don't see Superman and Wonder Woman having sex in that photo. Both of them are fully clothed. Superman is holding Wonder Woman and kissing her passionately. That looks more like love than sex to me.
It's not that Azzarello wrote it, it's what he wrote between Orion and Diana/Aleka. Superman has yet to slap a woman on the butt, call her legs, or tell her he's going to show her how he uses his tongue. After those things happen, we can discuss this again.