I disagree with this. Clothing does not preclude using all available forms of coercion, including using sexuality as such.
The idea of covering sexual organs might have little to do with modesty, and more to do with protecting those organs from damage, as they are crucial for reproduction.
But using coercion and violence to enslave a population had many side effects and anything that could be "demonized" was, so the slaves were taught that parts of their body belonged only to the gods or their representatives...
Yes, I can take this much further. Clearly I woke up and chose philosophy today.