I'm skeptical that such a line can ever be truly "settled." Sure, it can be settled in a particular social and technological context, but when those latter things change, the line may need to be adjusted.
TLDR: yeah, the law can change, but it's highly unlikely because "the United States Supreme Court has been more consistently protective of free speech than of any other right, especially in the face of media sensibilities about "harmful" words"
[1] https://www.popehat.com/2015/05/19/how-to-spot-and-critique-...
It's worth noting that no legally forbidden censorship has been happening with regards to the recent insurrection against congress.
> TLDR: yeah, the law can change, but it's highly unlikely because "the United States Supreme Court has been more consistently protective of free speech than of any other right, especially in the face of media sensibilities about "harmful" words"
But that's not a fixed fact of nature, it's a reaction to a particular social and technological context.
For instance, if someone discovers an idea instantly turns 10% those who hear it into murderous zealots (sort of like the poem in "The Tyranny of Heaven" by Stephen Baxter), that idea is going to censored hard and the Supreme Court will be like "yup, ban it."
Likewise, if some social change or technology renders the legal regime that the Supreme Court has created a cause of serious dysfunction, then Supreme Court is going to have to change that regime to accommodate. Idealism's great, but not when it doesn't work.
Yes, this is true as far as I am aware as well. But I find myself in a conundrum; had this "inciting" speech taken place in the town square or a public park, much of it likely could not have been censored because it would have been protected by the 1st amendment and the last 100 years of case law. Where, then, is the town square and public park of 2021?
Despite the fact that the legal protections of public speech haven't changed much in decades, the practical protections of public speech (as I discuss in greater detail in [1]) have indeed been eroded, because social media platforms and, apparently, web hosting and device makers are now the arbiters of the vast majority of speech. Free speech that only applies where virtually noone can hear you is a very limited free speech indeed.
The existence of Twitter, Facebook, etc. have accustomed people to the ability to air their opinions globally free of charge, however that is a very novel phenomenon. It's hard for me, having come of age in the 1980s/1990s, to see this as an inalienable right.