One could try to do some semantic weaseling about the meaning of "sexy", but if it's to be in the context of Internet porn it could hardly be very far from something like 'eliciting sexual arousal', and that's already pretty much a game of supernormal stimuli on trigger signals. If the machine is actually set to optimize for that, it should be able to create every impression that can be reached with subjecting real people to assorted body paints, hair cuttings, physical excercise, and surgeries .. and then some. And the computer generated media is already strikingly good and seems to keep improving.
Not sure I like the implications of a prospective situation where every real person looks dull by habituated standards, and maybe we don't have to end up there, but the post really comes across as a lot of opinions about what ought to be true and saying essentially nothing about what is.