Using our modern reading, the appearance of the dancemaster at the left is that of a normal heterosexual male.
The classical, curved and effeminate statue of a ganymede is that of satyr.
The 18th century interpretation is quite different:
The classical satyr has a beautiful, curving shape (ganymedes were part
of classical art and culture), while the dancemaster has a straight, and
angular posture, not beautiful at all: he doesn't fit into the view of
proper 18th century posture, the dancemaster is a fop!