There is a difference between “bawdy” humor, which Shakespeare engaged in when he talked about two people as “making the beast with two backs” and what we have degraded to with shock-jocks and the jackass Borat.
Also, those you mentioned who were engaging in bawdy humor during the Medieval period were not communicating to millions of people at a single airing. They were trying to entertain themselves.
And if you care to 1. cite where you copied that picture of the “manuscript” from so that I can authenticate it as being “medieval” and 2. link to a better image so that I can read the text, it may serve as better evidence of your argument. As it is, it is merely a grainy black and white picture of what looks like a type of satyr with words that are too blurry for me to make out. Don't take the "history" of Eco's Name of the Rose too seriously.
Such imagery was also employed after the invention of the printing press. The "limited" appeal was not the intent of the artist, but the limitation ofthe media.
"And if you care to 1. cite where you copied that picture of the “manuscript” from so that I can authenticate it as being “medieval”"
Camille, Michael. Image on the Edge: The Margins of Medieval Art. Cambridge: Harvard UP, 1992.