The documentary Behind the Curve explores this idea a bit. It follows die hard flat earthers around their daily lives to get to know them a bit more.

There's a running theme throughout the movie that these people weren't very happy with their lives prior to becoming flat earthers. Joining the "movement" gave them instant friends and a sense of direction. There's subtle hints now and again that most don't actually believe the Earth is flat, but they feel like "coming out" would ruin their reputation with their new community.

I get the sense that a lot of right wingers feel the same.

"Never believe that anti-Semites are completely unaware of the absurdity of their replies. They know that their remarks are frivolous, open to challenge. But they are amusing themselves, for it is their adversary who is obliged to use words responsibly, since he believes in words. The anti-Semites have the right to play. They even like to play with discourse for, by giving ridiculous reasons, they discredit the seriousness of their interlocutors. They delight in acting in bad faith, since they seek not to persuade by sound argument but to intimidate and disconcert. If you press them too closely, they will abruptly fall silent, loftily indicating by some phrase that the time for argument is past.”

― Jean-Paul Sartre