No one embraces "false" beliefs on purpose. To them it's as true as it gets - until it isn't anymore. In the 20th Century the biggest of these "religions" was Communism. And everyone knows what they did. Some people still pine for a Stalin - or a Hitler (I still remember some people referring to the dry-drunk ex-cokehead Dubya Shrub as "my President" - who said the Constitution was "just a goddamn piece of paper" and things would be easier if he was dictator).
People join to become better and more alive than they were before. And as the mythologist Joseph Campbell noticed, what people really want is to feel alive - and to be involved with something they see as bigger than they are. Even if it's a political party.
I've studied con artists for perhaps 20 years, which I know is the reason people fall for them is the hope of making their lives better. No one sets out to be conned.
When I was a teenager there were two big marginal religious groups - the "Jesus freaks" and the Hare Krishnas. I'd see the Hare Krishnas on the street all the time, begging for money (I saw one teenager tell a woman belonging to the Hare Krishnas she was "brainwashed").
In those days I had a friend who was a Jesus freak for a while, who later decided Carlos Castaneda was where the truth was at. Finally he gave it all up and became an airline pilot.
These days, all those cults are gone. But there will be others. There always are.
I have met con artists in person. More than one of them. Which is why I know "con" means "confidence." They bring you into their confidence. They're excellent at reading people, seeing their flaws and desires, and seducing these people into giving them money, power and attention.
They tend to be superficially charming and authoritative, but instead they are as empty as balloons. They tend to exhibit the Dark Triad - the real version of it, not the Manosphere's delusions of what it is. They have no conscience, no guilt, no remorse.
"Ultimately, what they sell is hope," writes Maria Konnikova in The Confidence Game. "Hope that you'll be happier, healthier, richer, loved, accepted, better looking, younger, smarter, a deeper, more fulfilled human being - hope that you will emerge on the other side you will be superior to the you that came in."
Isn't that what all ideologies promise?