They are Freemasons.
all this flat-disc-earth nonsense has its origins in freemasonry.
"zetetic astronomy" as it was called in the 1800's was made popular by a freemason named Samuel Birley Rowbotham under the pseudonym "parallax"
masonic 'debate clubs' are still called "zetetic societies"
the flat earth society was formed in the late 1800's and originally called the "universal zetetic society"
it was revived in 1970 by a freemason.
this guy Eric Dubay from the thread title, OP, and most of the videos spherical spams, is a freemason whose family has long, deep ties in freemasonry.
this thing has freemasonry written all over it, all up inside its DNA.
interesting, eh?