Aside from the ill-informed knock on the Middle Ages, I agree with the article as well. It is a completely non-Catholic tradition, largely Puritan, that is shy about the nude body.
The famous Michelangelo's Crucifixion has Christ completely naked, and that nakedness has a profound and truthful impact.
It is true that nudity can distract from the message, particularly in religious art. This is why it is uncommon in the Middle Ages, when all art was religious art. But not unheard of. Medieval England for example had a tradition of painted churches, -- most vandalized during the Reformation, -- and the paintings often depicted Our Lady bare-breasted, for the same reason Delacroix had Madame Liberty bare-breasted, to emphasize motherhood.