Fascism is a top-down ideology. It happens when capitalists feel that ordinary people are close to demanding a more equitable society, and they use it to divide society and assert their own authority. It is often described as a petit-bourgoise ideology because that is where the fascist capitalists find the most fertile ground - people who used to be able to afford a good life, but who can’t anymore. Of course, the irony is that the reason they can’t afford a good life is because the capitalists are siphoning off more and more of the wealth.