Private organizations often get a permit to put on events on public streets or in a public park, and open the event to the public generally. When that happens, courts generally don't let the police eject people who go to the event to express their own political views, even when the views criticize the organization or its patrons, and even if the organization wants the speakers ejected. The police can enforce content-neutral speech restrictions, such as limits on sound amplification. And if a group gets a permit to have a closed event, which only ticketholders can attend (especially common for events in government-run convention centers, but in principle possible even in parks or on sidewalks), the organization can select who gets the tickets. But if the event is generally open to all comers, people who come to speak can't be ejected.

Deferio v. City of Syracuse (N.D.N.Y. Jan. 31, 2018), offers the most recent example; here's the court's introduction:

"The First Amendment reflects 'a profound national commitment to the principle that debate on public issues should be uninhibited, robust, and wide-open.'" "The First Amendment offers sweeping protection that allows all manner of speech to enter the marketplace of ideas. This protection applies to loathsome and unpopular speech with the same force as it does to speech that is celebrated and widely accepted." "First Amendment jurisprudence is clear that the way to oppose offensive speech is by more speech, not censorship, enforced silence or eviction from legitimately occupied public space." These principles are by no means new. E.g., Whitney v. California (1927) (Brandeis, J., concurring). Yet they are strangely absent from the papers submitted by Defendants in defense of their actions toward plaintiff James Deferio, a Christian evangelical who regularly proselytizes at the Central New York Pride Parade and Festival …. While the dispute in this case may seem parochial—defendants Sergeant Jamey Locastro and Captain Joseph Sweeny forced Plaintiff to move approximately forty feet from the north to the south side of West Kirkpatrick Street—the issues presented here affect the heart of the First Amendment's purpose. As the Supreme Court recently stated, "Even today, [public streets and sidewalks] remain one of the few places where a speaker can be confident that he is not simply preaching to the choir. With respect to other means of communication, an individual confronted with an uncomfortable message can always turn the page, change the channel, or leave the Web site. Not so on public streets and sidewalks. There, a listener often encounters speech he might otherwise tune out." This [decision] affirms the importance of public sidewalks in the development of the marketplace of ideas and reminds state actors of the requirements they must meet in order to place restrictions on individuals' right to speak from traditional public fora….

And here are the facts, and the court's analysis of the defendants' argument that plaintiff's speech was constitutionally unprotected "fighting words":

Plaintiff is a Christian evangelical who attends public events in Syracuse and elsewhere in order to spread his religious beliefs. At the 2014 Pride Event, Plaintiff held a large sign that displayed a verse from the Bible regarding "the unrighteous." [The full text, which the court noted elsewhere in the opinion, was, "WARNING: Do you not know that the unrighteous shall inherit the Kingdom of God? Do not be deceived; neither fornicators, nor idolators, nor adulterers, nor homosexuals, nor sodomites, nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners shall inherit the Kingdom of God. 1 Corinthians 6:9-10." -EV] At the 2015 Pride Event, he held a different large sign that stated, "Thousands of Ex-Homosexuals Have Experienced the Life-Changing Love of Jesus Christ," which also provided links to relevant websites. He also used a sound amplification device to propagate messages regarding sin, judgment, and redemption…. Attendees at both festivals were unsurprisingly offended by Plaintiff's religious beliefs, which advocate for "homosexuals" in particular "to repent." But "offense" is not the standard by which First Amendment protections end. In fact, "if it is the speaker's opinion that gives offense, that consequence is a reason for according it constitutional protection." "After all, much political and religious speech might be perceived as offensive to some." … Defendants … [argue] that Plaintiff's speech at the 2015 Pride Event constituted "fighting words" and is therefore not protected by the First Amendment…. The "fighting words" exception to the Free Speech Clause is narrow and consists of a "small class" of expressive conduct. Fighting words "instantly 'inflict injury or tend to incite an immediate breach of the peace.'" "Offensive statements made generally to a crowd are not excluded from First Amendment protection; the insult or offense must be directed specifically at an individual." To determine whether such words are "inherently likely to provoke violent reaction," the Court must use an "objective standard"—whether "it is 'likely to provoke the average person to retaliation.'" First, the Court must note that Defendants spend the majority of its Statement of Material Facts and almost all of their deposition of Plaintiff cataloging Plaintiff's controversial comments regarding religion, politics, and homosexuality over the course of many years. See SMF ¶¶ 10–59. Defendants use these facts to gesture at the disturbing argument that all of Plaintiff's proselytizing, potentially forevermore, constitutes "fighting words." After citing to comments that Plaintiff published on Facebook, Defendants state, "While it is undisputed that religious expression is protected, Plaintiff's speech constitutes 'fighting words,' which by their utterance inflict injury or tend to incite an immediate breach of the peace." Defendants make no effort to distinguish between Plaintiff's speech on Facebook, at the relevant Pride Events, or at other events that Defendants catalogued. The Court hopes that this sentence was merely sloppy writing, though Defendants' focus on Plaintiff's speech outside of the events at issue in this lawsuit is worrisome. Turning to the 2015 Pride Event, about which Defendants argue with more specificity, the video evidence and Captain Sweeny's deposition do not indicate that Plaintiff used fighting words. Plaintiff attended the 2015 Pride Event with a large sign that stated, "Thousands of Ex-Homosexuals Have Experienced the Life-Changing Love of Jesus Christ," and provided links to relevant websites. In the limited time that he spoke from the intersection of West Kirkpatrick Street and the driveway into Inner Harbor Park, he made generally applicable statements regarding sin and religion. See, e.g., Dkt. No. 109 ("Time to repent people. You are not guaranteed tomorrow. No one is. Where's your love for God?"). Such generally applicable statements cannot constitute fighting words. Plaintiff did direct at least one insult at an individual: He called a woman a "homofascist," after she said, "Nobody talk to him. Do not feed the monkey." Given the context of their conversation, the Court must view this comment "as unpleasant but petty, and not sufficiently provocative to constitute fighting words." The term "homofascist" is frequently used to accuse individuals of trying to silence those who do not support the LGBT community. By combining "homosexuality" and "fascist," the user of "homofascist" invokes the "exceedingly common—arguably hackneyed—rhetorical device" of "comparing a disliked authority figured to a fascist leader." Williams, 535 F.3d at 77 (holding that, "as matter of law," "comparing the manager of a recreational center to a fascist dictator … does not rise to the level of 'so-called fighting words'"). While there is no indication that the woman who received Plaintiff's insult was a traditional "authority figure," such as the deputy commissioner at issue in Williams, Plaintiff's comment had the same meaning in the situation he faced, since multiple people were asserting the authority allegedly provided by the City to move Plaintiff across the street. The video evidence also indicates that the vast majority of the hundreds of attendees near Plaintiff ignored him. While a handful of attendees verbally accosted Plaintiff, and one attendee physically assaulted Plaintiff, the question is whether "the average individual" would be incited to violence by Plaintiff's words. Here, it is clear that the average individual was not incited to violence by Plaintiff's words. The Court notes that Captain Sweeny—the commanding police officer at the Pride Event—never once indicated that Defendants' words were likely to elicit a violent response. When asked by Plaintiff's lawyer, "Was there anything about [Plaintiff's] conduct that concerned you?", Captain Sweeny said, "His conduct, no." Captain Sweeny's Affidavit even takes pride in the fact that "Plaintiff was neither arrested nor charged with a crime, and, in fact, upon information and belief, [the Syracuse Police Department] pursued charges against [Plaintiff's] assailant." Defendants do not grapple with or even acknowledge these facts in their papers, which directly contradict their argument that Plaintiff's speech constituted fighting words. In sum, Plaintiff's speech at the 2015 Pride Event did not constitute fighting words, and therefore was entitled to First Amendment protection. As noted above, Defendants have not seriously argued that Plaintiff's speech at the 2014 Pride Event did not merit First Amendment protection….

And here is the court's analysis of the defendants' argument that moving Plaintiff was justified because of the Pride Event's permit: