Well that makes sense and I can understand the point there.
The commission of rape is always a power dynamic as it is forcing someone to do something against their will. Motivation is fairly immaterial as the crime is only commited when the power of one is imposed on the other. However, not all imbalanced power dynamics are a crime.
But isn't it the case in say, a scenario where a guy gets carried away and carries on regardless of the others protests, simply about lust? Let's not forget lust is an incredibly strong emotion to control and not necessarily anything to do with control or power, merely the urge to, er.....how can I put it technically...shoot your load?