I have to disagree with you about the looks of MLs. Many MLs are not prettier or have better bodies than WLs. Many have had kids with obvious c-scars or belly fat. This is why some want the lights dimmed in the room so you can't see their bodies.
As well, some RNT shops don't have shower facilities while some MLs will see many guys without any showers in between sessions. Therefore you wouldn't want to be licking her body or nipples after someone came over them if she hasn't cleaned herself properly.