I haven’t been able to find any case that defines who the incitement to commit violence against matters. You may be correct, and maybe you’ll have better luck finding a definitive explanation.
As for the “Brandenburg test”, I believe it remains the standard by which incitement, or “fighting words” are judged.
Case Commentary
“The conditions that must be met to impose criminal liability for speech that incites others to illegal actions are imminent harm, a
likelihood that the incited illegal action will occur, and an intent by the speaker to cause imminent illegal actions. This precedent remains the principal standard in this area of First Amendment law, since the Supreme Court has not revisited it. The absence of later decisions may result in part from the standard being constructed in such a way that it is very difficult for the government to meet. The slim possibility of success may make it not worth the effort to promulgate or defend a law in the area in most situations.”
Brandenburg v. Ohio: A state may not forbid speech advocating the use of force or unlawful conduct unless this advocacy is directed to inciting or producing imminent lawless action and is likely to incite or produce such action.
supreme.justia.com
Brandenburg v. Ohio: Permissible Restrictions on Violent Speech
By
Joseph Fawbush, Esq. | Reviewed by
Laura Temme, Esq. | Last updated September 21, 2021
“While Americans have the right to free speech under the First Amendment, that right has exceptions and qualifications. The First Amendment does not protect speech that seeks to incite immediate violence, for example. But what is the line between inciting violence and stating your opinions forcefully? It is a complex and nuanced area of the law.”
When does a speech with violent rhetoric cross the line into criminal behavior? That is the question the Supreme Court took up in Brandenburg v. Ohio.
supreme.findlaw.com
Again, you may be correct that the woman was lawfully exercising her 1st amendment right.
I believe, based on her actions; dressing all in black, wearing a Nazi swastika armband, entering a community center with mostly, if not all, senior citizens, that it was her intent to incite a negative reaction, up to and including violence.