There is the underlying issue. If you don't fight for those people who you don't agree with or despise although legal you will eventually loose your freedoms too.
If you want free speech you need to protect all of it.
On the other hand, if I facilitate people arguing for fascism I will also eventually lose freedoms if they win. And in the meantime make a number of other people just that little bit more miserable.
"Fascism" has never won by arguing, though. It isn't even a well-defined ideology! Fascism means using political violence (i.e. beating people up, or worse) to seize power in something very much like a coup d'etat; it really is as simple as that. That's not free speech, and it's not even something that our government protects. Threats are illegal. Purported "speech" that poses a clear and present danger is illegal.
> It isn't even a well-defined ideology! Fascism means using political violence [...] to seize power in something very much like a coup d'etat; it really is as simple as that.
First, though fascism is isn't particularly well-defined, it is definitely better defined than that (since you're describing a tactic rather than an ideology), and that just isn't what fascism means[0], second, even if it was, it would still be possible to advocate for it without crossing that line and leave facilitation to other (usually covert) channels.
Still, although advocacy for fascist views would be legal, I have no particular problem with public platforms restricting speech that promotes those views[1].
The analogy elsewhere in this thread to the phone system is flawed, as that implies regulating private speech.
OTOH, so long as money equals speech, there is an argument for creating payment infra that is more along the lines of a public utility or common-carrier for transactions that may not discriminate, since there are other categories of public speech besides fascism that are often unjustly denied access to payment infra.
Missing from that page is the preamble in which he describes growing up under Mussolini.
> Purported "speech" that poses a clear and present danger is illegal.
Speech that leads to or implies violence at slightly greater remove is, however. Circulating pictures of targets with people's faces on; calling for violence or that people should arm themselves against an outgroup; that kind of thing.
Bold hypothesis: fascism has never won in a free-speech environment. Only in an environment where everybody was a-ok with opposing opinions being suppressed, which allowed fascists to suppress different opinions.
Following this reasoning, GP's stance enables fascism.
> Bold hypothesis: fascism has never won in a free-speech environment
Ah, why look at history when we can have hypothesis! I mean, you could have chosen some wrong or out of context examples of fascism to cite, but instead it's much easier to just pretend, right?
Fascism didn't win by arguing alone, but arguing was a very important part of their strategy - please notice that the creator of fascism, Mussolini, became famous as a (vitriolic) journalist.