I could be wrong but I almost get the impression that Flat Earthers are in reality sophisticated trollers. If they are not then I must ask how does any of this relate to the Faith? Why are you so strident in your beliefs?
The only way to find out whether this is nonsense is to do your homework; study flat earth. Get to know both sides of the argument. In the meantime, flat earth is the truth, so it has everything to do with the Faith. The Church condemned heliocentrism/spherical earth because that model was contrary to scripture. This was well known during the Galileo Affair. When science finally cowed the Church into silence and claimed they'd proven earth to be a moving globe, that Galileo was right, the Church has became the butt of jokes. This put scripture and the Church in the stupid, archaic realm, totally "behind the times" and utterly mistaken. NASA and pagan science has capitalized on this skepticism of the Church, big time. They own the microphone and speakers when it comes to the science of the world and the cosmos. And they are gaining incredible power with the money generated by it. In fact, heliocentric science has so empowered the Big Banger evolutionists, with the masses literally worshiping false science by pouring billions of dollars into false space programs, evolution, fake global warming endeavours, lies about dwindling resources which must necessarily be limited on an orphan planet (to the advantage of those benefiting from pretend scarce resources). The entire paganization of earth is utterly dependant on heliocentrism/spherical earth. The big boys running this operation don't call themselves "globalists" for nothing. The sphere itself is the basis for relativity and consequently, for lies. After all, level isn't level, its curved. Up isn't up, its out. West isn't actually west, its relative. People are upside down to each other on a globe...and yet, we're all said to be standing upright. Such lies generate new lies and so on. Flat earth has everything to do with the world because God already told us about our world in scripture. He described it as having a face, with a dome over it that divides the upper waters from the lower waters, that the sun and moon are lights, not worlds, that the earth has a foundation, it is set on pillars and it can never be moved. Denying what God taught in scripture, what the Catholic Fathers taught, what the Church taught, then it becomes clear, this is a matter of faith, and therefore salvation. If you wonder why someone might lose their soul over this, remember, the world at large has abandoned what the Church taught and embraced pagan science as their religion-choice for facts. Oh, and just try to tell them the truth! They'll literally CRUCIFY you. If it doesn't matter, why do they get so violent? The fact is, it does matter. And it is a religion to many, many people. Interestingly, it also turns out that it is also a matter of corporal life and death. And the Satanic powers-that-be are sitting fat and happy in their Re-Creation of the world ready to scrape in all the rest of the related monies they can before pulling the plug on the economy and/or going to war to bring about their ultimate goal (because we're so overcrowded): depopulation.
Yep. Flat earth matters.