Its rather funny, because in above clip he shows the usual Libral ignorance about the Medieval Church. They did not believe that the world was flat. When it came to the geometry of the Earth, the establishment were correct and Columbus was incorrect. His stupidity being rewarded with fantastic fame, status and wealth.
As far as I can make out, the modern flat earth movement in significant part is a result of this Liberal trolling in the nineteenth century. We've seen this kid of successful trolling by the Right as well. Where they invent a really dumb idea, attribute it to the left and then people on the left buy into it.