(The nude-but-not-sexual viewpoint is pretty valid, but some of the fine art is definitely sexual once you know the context, and some of it was controversial in its time e.g. https://en.wikipedia.org/wiki/Le_D%C3%A9jeuner_sur_l%27herbe )
Source? To my reading, this is a decisively late Christian/Puritan perspective on sex and the human body.