How do you kill an idea?
By replacing it with another idea.
Duhh, but how do you do that.
Bringing democracy will not help.
Calvinism once spread to Northern Europe at massive speed. I do not think it was the message that did that, but what came with it. It was imperative that everyone learned to read. So, it came with schooling, for everyone, regardless of status, and in some areas even regardless of gender. It came with empowerment for the people.
Something like that may help spread a new idea. But, what could it be? Something that can spread in a grassroot way.