I think if I had a lot of fun and comradery going to my Earth is flat club on a frequent basis and drinking beer with those guys and getting patted on the back for my opinions I'd probably be pretty unwilling to let a little thing like the Earth not really being flat get in the way, it's besides the point.
There were several of them who refused to go on the trip, which they were offered for free, and then when other people went on the trip, they claimed that footage of the trip was faked in some way.
I agree, the people are doing good, who went there and admitted the truth of what they were seeing. There’s a whole category that are even further gone than that, though, to where their brains will actively shield them against something that might threaten the whole self-referential structure.
They knew they couldn't continue the grift they're operating under when confronted with something they flat out denied the existence of as it goes completely against their model.
Nearly all the content creators know they're basically cult leaders and just want their own flock to pay for their lifestyles without having to really do anything.