If he is in a public place with his stand, he is subject to the same rules of conduct as anyone else. His speech went well beyond what is legally permissible as "free speech" . He breached that line several times.
"In Chaplinsky v. New Hampshire (1942), the Supreme Court held that speech is unprotected if it constitutes "fighting words".[27] Fighting words, as defined by the Court, is speech that "tend[s] to incite an immediate breach of the peace" by provoking a fight, so long as it is a "personally abusive [word] which, when addressed to the ordinary citizen, is, as a matter of common knowledge, inherently likely to provoke a violent reaction".[28] Additionally, such speech must be "directed to the person of the hearer" and is "thus likely to be seen as a 'direct personal insult'".[29][30]
One legal commentator has suggested that, along with fighting words, speech might be unprotected if the speaker intentionally, knowingly, or recklessly inflicts severe emotional distress.[31] However, the United States Supreme Court has not implemented such an exception, and even if it does, the exception would be probably be limited to private figures. The Court held in Hustler v. Falwell (1988) that satire which could be seen as offensive to a "public figure" is fully protected.[32] Such speech is rooted in a historical protection of political satire.[33] A notable example of a case involving offensive speech was the Court's decision in Texas v. Johnson (1989), which struck down a law criminalizing flag burning in Texas.[34]
Threats of violence that are directed at a person or group of persons that has the intent of placing the target at risk of bodily harm or death are generally unprotected.[35] However, there are several exceptions. For example, the Supreme Court has held that "threats may not be punished if a reasonable person would understand them as obvious hyperbole", he writes.[36][37] Additionally, threats of "social ostracism" and of "politically motivated boycotts" are constitutionally protected.[38] However, sometimes even political speech can be a threat, and thus becomes unprotected.[39]"
https://en.m.wikipedia.org/wiki/United_States_free_speech_exceptions
