We can actually tell you the name of the person responsible for starting the Barbie crotch style in western art: Praxiteles.
You can't complain to his manager, because Praxiteles lived and died in the 4th century BCE. Also his manager might have been Alexander the Great, who's probably too busy to listen.
At the time Praxiteles was working, Greek sculpture had certain conventions. Men were depicted heroically nude, dicks out. Meanwhile, sculptures of women were always clothed.
Praxiteles decided to mix things up. Working on a sculpture for the Temple of Aphrodite at Knidos, Praxiteles made the decision to depict Aphrodite as nude, emerging from a bath.
Roman copy of the Aphrodite of Knidos. Museo Nazionale Romano, Ludovisi collection