I agree, there are people for whom their avatars are as direct extensions of themselves. You have full autonomy over your character through their appearance and actions.
It's unfortunate to know that some people are perving your avatar's representation on their client, but unfortunately anyone might see someone passing down the street IRL and lust after them and/or draw inappropriate art of them without their ever knowing. That's simply a risk you take by existing in the world with other people. People don't need a mod in order to produce nude recreations of your character, so I'm not sure how necessary it is for an MMO to crack down on this kind of thing beyond suspending players who happen to be caught.