It's not like he's an idiot or a brutal medieval warlord. He's smart enough to be a likely head of state in a modern nation where everyone accepts the idea that all humans have basic rights. He's experienced in dealing with other people in the exaggeratedly civilized ways that statesmen interact with each other. And then -- assuming that the allegations are true -- he tries to rape a stranger who's cleaning his room.
This isn't an isolated event. Rumors are that he's been this way with women for a long time: "Thierry Ardisson, a French talk show host, tells the Mail that she had 14 female friends who spoke of instances when Strauss-Kahn attempted to "jump" them." (John Hudson, could we make this a separate item than his consensual relationships? It's no problem if he's having a promiscuous consensual sex life. That's something intelligent, civilized humans can do. Rape is not like that.)
I understand the race, gender, and class dynamics that go into the explanation, but only from the outside. They don't take me any further in putting together a coherent picture of what it's like to be Dominique Strauss-Kahn, see someone cleaning the room, and decide to rape her.