I think the joke works because people have been pushed for years to be ashamed of pointing out certain anatomical parts out of fear of being accused of such things that you mentioned, making it an all around taboo topic. A breast is a breast and a thigh is a thigh, regardless of sex. There’s no shame in admiring such features if they’re pleasing to the eye (or in the case of the post, taste), we are visual animals after all and the human body is a biological marvel that can cause awe. And no, I don’t think it’s a common question. Perhaps amongst the socially inept, but it’s always been rude and shallow to objectify people based off their physical features. Dehumanizing? Depends on the context. Everyone has preferences, whether you verbalize it or not. In this case, you are being asked for your preference and to verbalize it. I don’t understand what part of that is dehumanizing, we’re not reducing anything here, just pointing out a preference. To say there’s not a part of a body that makes you go 👀 on occasion would be insincere, as something as simple as ordering chicken proves.