I think you're mostly in the ballpark (mostly), but it's still highly misleading to associate so loosely and lazily. I mean, you have entities and corporations in which the founders truly are fascist / deeply right-wing, and it's worth calling them out and making that clear to as many folks as possible.

Disingenuously calling Substack "fascist" because it allows wacko subgroups to operate is the exact same argument you could make about Reddit, Facebook, and several others. It doesn't necessarily mean that the founders and showrunners are in fact fascists by definition, even as yes, the real-world definition of fascism and late-stage capitalism are indeed deeply intertwined.

So, no-- I reject the commenter above's disingenuous label. And a big part of the reason why we use words and language is to point out subtle differences in things. Because we don't have to be cavemen who lump disparate things together out of ignorance, fear, and whatnot.