William C. Killian's speech was constantly interrupted by boos and heckling Tuesday evening at the Manchester-Coffee County Conference Center.
The meeting was billed as "Public Disclosure in a Diverse Society" and was sponsored by the American Muslim Advisory Council of Tennessee.
The Chattanooga Times Free Press reported shouts of "traitor," ''serpent," and "go home" were directed at Killian by a crowd of more than 300 people. Others, who had staged a protest outside before the meeting, were angered at being turned away when the room reached capacity.
Some who remained outside hurled labels including "communist," ''socialist" and "Muslim" at law enforcement officials who denied them entry.
Inside, Killian told the crowd hateful speech is allowed by law, but threats are not.
According to The Tennessean, former "Saturday Night Live" cast member Victoria Jackson was among the protesters. Jackson now lives in Tennessee.
"The Constitution and Sharia cannot coexist," she said. "Islam is evil."
After Killian spoke, Kenneth Moore, FBI special agent in charge of the Eastern Tennessee District, made comments to the crowd.
"Our presence here tonight has generated some controversy," Moore said. "People think we want to step on and stifle their First Amendment rights. Nothing could be further from the truth."
Organizers of the forum said they chose Coffee County because of Facebook posting last month by county commission member Barry West. It showed a character sighting down the barrel of a shotgun with the legend, "How to wink at a Muslim."
West later apologized for the post.
Not everyone who came to the forum was shouting epithets. Elaine Smith, 55, of Bedford County said she became afraid of other members of the audience.
"I came here because I wanted to learn something . but I couldn't hear because the audience was so disrespectful," Smith said. "I cried when I got here. It makes me really sad especially because these people say they're Christians. The God I worship doesn't teach hate."
Gene Policinski, senior vice president and executive director of the First Amendment Center, said public officials are held to a higher standard, but that doesn't mean their expression is limited.
"There's nothing in the First Amendment banning anyone to say things that people find repellant, distasteful, repugnant or even bigoted. The antidote that our founders provided for speech is more speech, not less."
WSMV-TV said Killian left the forum by a door that allowed him to avoid reporters as he left.