There is insufficient data

So, there's nothing in the form of actual evidence for asserting liberalism as exceptionally a boogeyman for fascism.

I'm hammering this point here, but I want to make it clear why - I believe in a socialist future, or at the very least a post-capitalist future. Capitalism has overstayed its welcome and needs to go, for the good of human society. But capitalism and liberalism are not the root causes for all of our problems. A handful - a handful of big ones, yeah, but only a handful. I dislike it when people start asserting that socialism would 'fix' everything by simple fiat. It's no different than some free market fetishist insisting that the market will correct itself to come to the most efficient solution.

but we can look at the incentives of the system. If implemented as an authoritarian state running the economy a la state capitalism then we’ll see similar concerns. If implemented as a syndication of workers unions then we would not.

What, precisely, do you mean by a syndication of workers' unions? Market socialism? A planned economy by consensus?

It doesn’t take a double blind study with control groups to make a statement about what a system incentivizes. A distant billionaire owner doesn’t care about polluting your city, but you do.

That's just the thing - you already see this dynamic with homeowners. Homeowners - as in, individual homeowners, not corporations or firms - use the municipal tools at their disposal to (sometimes) effectively fend off outside interference. They utilize their power and self-interest as a class to reject the imposition of capitalist firms seeking profit. But it's not out of any sense that "Poisoning the air for money is bad" - these are largely the same people who vote in Republicans to the state legislature, and cheer on the opening of a new coal plant - as long as it's not near them.

I know that the response is going to be "But if society's culture was different they would act differently", and that comes back around to point 1 - there's no fucking proof of the supposed changes.

A distant billionaire owner doesn't care about polluting your city, but neither does the factory worker upwind of you. It's NIMBYism, not wealth disparity. The billionaire cares just as much about the coal plant in HIS backyard as the local homeowner does - and the average local homeowner cares about the coal plant in some distant homeowner's backyard about as much as the billionaire. And if you have a bunch of workers' firms operating in the interest of the workers within them, those firms are necessarily going to make choices that maximize their gain (whether those gains are in stability of function, social capital, etc) and minimize their losses - including by, say, polluting downriver where nobody gets their water from anyway - nobody the workers know, at least.

I am 100% in support of overthrowing the current system. But I don't expect what comes next to be a panacea to humanity's problems, and neither should anyone else. When we make the change, it will not cure our problems. We'll be fighting a good 80% of the same fights we are now. Fuck's sake, even in actual nonprofit, nonhierarchal community groups today you see all kinds of bullshit worm its way from the cretins within. We will be voting against fascists who want to abuse the system - whatever form that system takes - for their own power. We will be arguing with locals over why the community coal plant proposed in someone else's town which will make their electric bill go down is a bad thing. We will be telling Joe Schmoe that voting for the blathering dotard of a union leader running for the executive council this year because he 'tells it like it is' (with 'like it is' being 'confirming my prejudices') is bad fucking citizenship. We will be protesting the neighboring Ohio Workers' Council for not enforcing the standards of pollution they agreed to abide by.

We will be fighting the same fights. And to pretend that liberalism is the root cause instead of just incidental to most of these problems is... absurd. Liberalism, thus, only 'leads to fascism' in the same way that every extant system leads to fascism; and in the same way that any theoretical system considered will lead to fascism.

Fuck.

That being said, the form of neoliberalism which became popular in the 1980s IS creating an environment ripe for fascism - not uniquely, not even the worst environment possible for fascism - but causing formerly functioning societies to collapse in on themselves is definitely a bad fucking environment for fighting off blowhards who promise to 'fix everything' if only they get ALL the power.

As Joseph Stiglitz himself says:

"Rather, the answer is something along the lines of a rejuvenated European social democracy or a new American Progressive Capitalism, a twenty-first century version of social democracy or of the Scandinavian welfare state,"

... I actually don't agree with that, I'm a bit more radical, but the point is this - no system is going to fix all of our problems. No system is going to not 'lead to fascism' in the same sense that liberalism 'leads to fascism'. And by bandying these ideas about, by insisting on the utopian worth of the ideology and the society it will supposedly create, you set up idealists for quick disillusionment (or conversely, increasing radicalism to root out the shadowy 'enemy' which is clearly stopping the perfect society from coming to be) and the marginally-political to reflexive reaction - to actual conservatism, as in, keeping the status quo, like dipshit centrist Dems do. Because as politically uninformed as they are, most of them aren't complete morons - they see when someone promises perfection, they're likely to deliver anything but. And no amount of theory is going to overcome that obstacle, because for once, they're right.

... you don't have to respond to this, actually. I think I ranted myself out.