Why am I so passionate about the flat earth?

Because it's true, it's liberating, it explains everything (finally), and it totally matches up with reality. Something as foundational as THE BASIC NATURE OF THE WORLD WE LIVE IN has to "matter", don't you think?

But as a person who discovered this only recently (a few years ago?) I know how I felt and feel about it.

Imagine a powerful charismatic man like the Antichrist -- more intelligent, better with arguments/debate, and with a sharper mind that most current "flat earth" proponents today. Imagine how convincing he will be, how he will put it all together.
He might even (after taking power) arrange various voyages to Antarctica to prove it. Maybe even reveal continent(s) outside the ice wall. Maybe do a partial re-enactment of Operation Dominic, when they sent rockets STRAIGHT UP to explode against the firmament (they wanted to "get out" -- they failed) -- this time with large crowds watching.

Now imagine how people will react. They will feel that EVERYONE, EVERY ORGANIZATION has betrayed them. They will adhere to said Antichrist out of gratitude and devotion. He will appear to be a heroic bringer of truth, smasher of error/delusion, and wonderful promise for the future.

Do we want to leave this "reveal" to the Man of Sin? God forbid!

No, Traditional Catholics can possess this truth TODAY, and then they won't be floored when the Antichrist reveals it later.

TRUTH MATTERS. It always matters. This is just another way in which it matters.

Why do I want to steal the Antichrist's thunder? It should be obvious -- to reduce, as much as possible, the number of converts he will make. I want to have that many more souls that will NOT adhere to him, and hence be saved for all eternity. I'd say that's a noble cause.

The more insanity/errors you have in your head, the more things the Antichrist can "heal" you from, like when Our Lord healed people of various diseases. Taking away the blindness/error from their minds would be just as compassionate and just as important.
A man who wakes you up, who gives you the truth, is a GOOD GUY, at least in that aspect. You are inclined to believe he is a good guy IN GENERAL, because truth comes from God.

It also matters because an FE would totally destroy modern Big Bang cosmology, which requires rotating and coagulating spheres to even be remotely credible even to those who don't know that it violated the basic laws of thermodynamics.  There would be very few atheists left in the world.  Some of the leading FEs went from atheist / agnostic to at least have some natural belief in, aka knowledge of, God.

Ultimately, it is my theory that AntiChrist will present as an alien, will shape-shift, and declare that Jesus, Moses, Abraham, and Mohammed were all aliens, come to intervene in human history to improve their condition.  He will simulate the miracles of Our Lord, but then will be struck down attempting to simulate Our Lord's Ascension.  That:s about the only scenario I can see which would fool nearly the entire world and shatter faith.

It would seem to appear that a large number of Catholics are being demonically deceived either directly, indirectly or both about the Earth being flat or a large number of Catholics are being demonically deceived either directly, indirectly, or both about the Earth being a globe.  It obviously can't be both.  Does the Church, Herself teach us one way or the other and if not why not since it appears to be of some significant (spiritual?) importance?

Interesting enough no doubt, there are Catholics on both sides of the question who every day recite an act of faith which includes words which in essence say, "I believe these truths and all the truths which the Holy Catholic Church teaches because Thou can'st neither deceive nor be deceived."

The Novus Ordo is destroying far more souls than any debate about the shape of the earth could ever touch.

 Father Chazal's sedeimpoundist position I find perfectly acceptable.

Me too!  

Why am I so passionate about the flat earth?

Because it's true, it's liberating, it explains everything (finally), and it totally matches up with reality. 

But it doesn't:

https://www.cathinfo.com/the-earth-god-made-flat-earth-geocentrism/flat-earth-myth-debunked-put-to-bed/msg1009248/#msg1009248