I think we saw a glimpse of it in the post to which I was responding there. You spend your entire life trying to be patriotic, saying the Pledge of Allegiance, saluting the flag, denouncing the flag burners and the kneelers, and some of us lived through the Cold War as we watched crowds chanting "USA! USA! USA!" during the US vs. Soviet Olympic Hockey matches. We were PROUD, extremely proud, of the fact that the US won the space race and beat the Ruskies to it ... one of the greatest achievement of mankind. What utter humiliation that would if it were definitively exposed that these were a fraud. US could never live that down, and our national pride would never recover from such a blow.
Patriotism is a virtue, but I became a Traditional Catholic and learned that "Freedom of Religion" wasn't this great thing it was cracked up to be and saw the evils of the French revolution, to which the US revolution was closely related. I had always been proud of the US effort in WW2. Then I learned that the entire war was a Globalist fraud. I used to enjoy saluting the WW2 veterans that would make appearances in parades and whatnot. But then I realized that the nukes on Hiroshima and Nagasaki were crimes against humanity, as was the bombing of Dresden. I used to oppose the Hippies who protested against the Vietnam war, but then I realized that the whole thing was a fraud staged by the Military Industrial Complex (and learned about Gulf of Tonkin). We found out about 9/11, and from there the floodgates were opened. Pretty much everything was a lie. Everything. So this is very difficult to take.
Some people get into science and physics, and they learn a lot of neat and interesting things. We grow up with globe and planet mobiles over our cribs and see a globe the minute we walk into a classroom. By 2nd or 3rd grade we're building solar system models with styrofoam balls. Some of us get into science fiction. I was an avid fan of Star Trek and also enjoyed Star Wars (to a lesser extent).
It's difficult to learn that everything you thought you know and believed in and supported was a total lie. It's heartbreaking really.
I recall when I first came to the conclusion that the earth is certainly flat. It was shocking. My entire life I thought one thing about the universe and creation, and to realize that it was a lie for 53 years, that's hard to take. I tend to encourage those against FE to make a thought experiment. Just imagine for a minute that you did come to know for a fact that the earth is flat. Try to then experience the emotions you'd feel upon finding that out. Your brain just kindof spins.
By the time I had started looking into FE, a lot of my "paradigm" had already shifted, with 9/11 and all the other things I mentioned before, so the thought that the government would lie to us and that we're controlled around the world by our Jєωιѕн globalist masters, that part was not shocking to me. And so it was for that reason that I at least decided to look at the evidence with an open mind. But this one was still difficult to swallow, 1) because we have been strongly programmed with this our entire lives, and 2) because FE is absolutely ridiculed and Flat Earther has become synonyous in common parlance with "nutjob". It's not easy to take the constant ridicule.
But I submit, as I did in the post that you cited that if it were THAT crazy, people wouldn't be hostile to it. They'd just make the circular motion with their finger by their ear as they walked past. So, as I suggested, the reason is two-fold.
1) there are a lot of good, strong arguments and compelling evidence for the position (it's not so far out in left field as to be ludicrous)
2) it threatens people psychologically for the reasons I articulated above
If EITHER one of these weren't the case, then we wouldn't have people out there almost dedicating their lives to debunking it. If it was so insane as to not even be remotely credible, people wouldn't feel threatened by it. But, then, if the evidence were overhwelming, people wouldn't be so hostile to it if it didn't threaten them on some deep psychological level. In that case, they would actually consider the arguments objectively and with an open mind.
And the fact that the FE movement is growing (despite Big Tech suppression) means that there's enough evidence out there to make it very, very compelling to intelligent people. Lots of people have an aversion to being classified and derided and mocked as lunatics, and yet they come to believe it anyway. Every single one of the main FE proponents tells the same story. When they first started looking into it, they too thought it was ridiculous and mocked it and wrote it off. Many of them set out to debunk it, but then ended up finding themselves won over.
What I see with nearly all the ardent defenders of Globe Earth is that they have CLEARLY made up their minds ahead of time. They beg the question, and then engage in confirmation bias, taking whatever evidence they can find in favor of their position as definitive smoking-gun slam-dunk proof, and then filtering out the evidence that suggests the contrary (after all, we KNOW the earth is a globe, so it must be wrong). So it's just a question of coming up with a reason WHY it's wrong. THAT it's wrong is never in doubt in their minds. And that's a huge block that prevents them from really and honestly considering the position.
After I came to the FE conclusion, I did what I always do on such issues. It's like a scholastic method. I pretended that I'm a Globe Earther and am trying to prove to a Flat Earther that the earth is a globe. I find that I simply can't do it. I'm not talking about sophistry where I say, "look at these pictures from NASA" (because I honestly can't trust NASA as far as I can throw a Space Shuttle). I'm not talking about sophistry where I would just say the magic word "refraction" while waving my magic wand to make stuff go away. It's easy to say that refraction COULD cause the "see too far phenomenon" ... EVERY ONCE IN A WHILE. But to claim that it's almost universally present and tht "see too far" is so easily and readily reproducible, and that this refraction just perfectly curves around the globe in the same ratio, and that it even works bi-directionally when you have to have an increasing density gradient, but then if it's increasing in one direction, it would be increasing in the other. I simply can't believe that all that long-distance photography from 300+ miles away showing mountains that should be hidden under miles of curvature are simply refracted perfectly around the globe. I can't believe that a pressurized atmosphere can exist adjacent to a vacuum. I could sophistically say, muh gravity, but I don't believe that the force of gravity is anywhere nearly strong enough to prevent an infinite vacuum of space from just ripping the atmosphere off the planet. I see these steel tanker cars absolutely crushed because there's a vacuum inside and yet I'm supposed to believe that gravity, which can't hold a helium balloon down on the ground could overcome this. If I put a vacuum chamber above a chamber filled with air, it'll "suck" the air right out of the chamber without gravity being able to keep it down in the lower chamber. I could go on and on, but I find that I could not convincingly argue the globe position. I've done the same thing with, say, evolution. I'm trying to prove evolution to someone who doesn't believe in it. I couldn't even come close to making a good argument for it.