The petite bourgeoisie play an outsized role in fascism, but they are more like the footsoldiers. Fascism is essentially to capitalism in crisis what liberalism is to “pleasant” capitalism. When capitalism deteriorates materially, the petite bourgeoisie is pushed towards proletarianization, so the bourgeoisie stokes the hatred of the petite bourgeoisie towards other social groups, often along ethnic lines (though not exclusively).

The bourgeoisie uses the petite bourgeoisie to root out radicalized sections of the proletariat that have begun to organize against capital, which is the general proletarian response to decay. This is why fascism is inherently anti-communist.

There are people who know far more about fascism than me here, and I expect them to chime in, but this is how I understand it.

The big bourgeoisie are usually comfortable where they are. It’s the petite bourgeoisie that are squeezed between much larger and more powerful capitalists above them, threatening to swallow their market share, and workers that steadily gain more strength below them, threatening their bottom line.

There’s an interesting connection to antisemitism here. We’re very familiar with the antisemitic tropes of Jews controlling every big financial or media institution, which maps to the material reality of large capitalists always having the edge against small ones, but there’s also a lot of tropes about Jewish workers subverting their employers’ interests. This is related to cultural Bolshevism and similar narratives in the 20th century. Nowadays I think the closest analogue is the 4chan j**t meme against South Asians taking jobs in tech fields, or the anti-immigrant hysteria.

The point is that people in the middle of the class struggle are the most likely to be the base of support for fascism because they are the ones who stand to lose the most from socialist revolution (the ultra rich can just use their connections and capital to move to another country and still be ultra rich).

Fascism arises from the class despair of the petit bourgeois. They see their position being weakened and seek to hold onto it through any means necessary. Socialist revolution isn’t a way out for them because that deprives them of their superior socio-economic position above the working class. I think I got this from Trotsky or Gramsci though I can’t remember which. Maybe this is what you are looking for?

As property owners the petite bourgeoisie benefit from capitalism, yet they are naturally disadvantaged in the capitalist system when compared to the haute bourgeoisie. The natural fate of the petite bourgeoisie in capitalism is to develop small business ventures that will then be bought out by bigger businesses at the expense of the small capitalists that own those small businesses. This is the competition of the “free market” in action. Socialism isn’t the solution as they lose the privilege of bourgeois class status under socialism and so fascism was born as a solution whereby the liberal order established by the haute bourgeoisie is subverted & usurped so the petite bourgeoisie can seize control of the capitalist system.

Of course what actually ends up happening is that the haute bourgeoisie infiltrate and coop the burgeoning fascist movement when the threat of radical Leftism emerges and grows; this is why big capitalists always end up coming in to bolster fascist movements, spread their message, and finally take over in the role of leadership eventually pushing the petite bourgeoisie out of power in the very movement designed to empower them.

This happens because the the bourgeoisie as a class are motivated by individual profit and have no collective identity. Even if they’re class conscious - and they often are - they rarely display an actual sense of class solidarity and the illusion of such is driven entirely by a desire to protect their own self-interest; not because they care about each other. Thus the bourgeoisie are just as likely to be at each other’s throats as they are to unite in suppression of the proletariat.

most of the answers are pretty clear, but these are my two cents:

-petit bourgueoisie is attracted to fascism when there’s another crisis in capitalism, because they sell them the idea that their issues are caused by migrants/leftists/jews/lgbt/whatever and not the contradictions of the system

-petit bourgueoisie want to keep their privileges real or assumed, because they feel superior to the “dirty wage workers” and they feel morally superior to those “corrupt oligarchs and cronies” that “didn’t work for it” and they deserve being treated better and bettering the underdog class is compared to “make everyone equally poor” so they shouldn’t allow unionization, affirmative action or state intervention and it’s just need some heavy-handedness to “restore the good ol’ days”