The episode doesn't tell us if Pius XIII read McLuhan, and his notion that the less presented, the more the viewer is attracted and involved, but Pius understands it, as well as if he had read the relevant chapter in Understanding Media, or sat in any of McLuhan's classes in the Coach House at the University of Toronto when McLuhan held forth there through the 1970s. (I was there several times in the late 1970s, and again just this past year.)
McLuhan was a devout Catholic, and likely would have been offended by a lot of what the young Pope says and does. But McLuhan couldn't deny that Pius knows his McLuhan, whether he explicitly acknowledges it or not.
The other important theme in tonight's episode is the power of Sister Mary. She is the closest to the Pope, and some even think that she thinks she and the Pope are co-Pontiffs. At this point, it's difficult to say what she's really thinking, but she may have in mind that's she's in effect the first female Pope, working through Lenny aka Pius.
The young Pope of course wouldn't want that. He loves his power, at least as and maybe more than God. And I await to see how the story unfolds next Sunday.
See also: The Young Pope 1.1: Beyond Iconclast