A neighborhood meeting in Park Slope descended into a belligerent free-for-all on Wednesday night, after the event’s invited speaker spewed conspiracy theories about a pedophile-linked bike lobby, then shoved a well-known cycling advocate.

The meeting was the second held by Citizens United for Safety, a group founded by local resident Myra Manning to call attention to the “lawless” conditions created by new curbside bike lanes on both sides of Ninth Street. The bike lanes, along with pedestrian islands and other traffic-calming measures, were installed last summer between Prospect Park and Third Avenue after a driver blew through a red light, killing two children and injuring two others, including a woman whose pregnancy was terminated as a result of the crash.

Manning, 76, has circulated a petition against the bike lanes that she says has garnered more than 1,300 signatures; earlier this year, she met with Brooklyn Borough President Eric Adams to discuss her safety concerns.

But before the discussions about the changes to the street could even begin, control of the meeting was turned over to Manning’s guest, John DeLiva Halpern. Reading from prepared remarks, the self-described cultural and climate activist warned of the “paid activists” in attendance with Transportation Alternatives. Funding for the nonprofit advocacy group, he alleged, “comes from the likes of billionaire Steve Ross, a crony of Jeff Epstein, and an elite group of backers.”

When audience members snickered at the claim, Halpern stood up on a chair, jabbing his finger at the group and shouting: “You wanna clown around with me? You wanna clown around with me?”

The scene in the steamy basement of the Church of Gesthame only deteriorated from there.

“Yeah I shoved him,” Halpern said afterward. “It’s theatre, we’re all performers.” pic.twitter.com/IhJjToNcK0 — Jake Offenhartz (@jangelooff) September 26, 2019

Over loud objections, Halpern presented an exclusive look at his unfinished film, “Betrayal on 14th Street,” a fawning portrayal of the Manhattan residents who have successfully stymied a busway planned for the corridor, and are seeking to rip out two adjacent bike lanes.

Roughly half the attendees jeered at the film, decrying it as propaganda. A man in an FDNY shirt, who declined to give his name, threatened cyclist Brian Fulton-Howard: “I’ll beat your ass.”

Amid the commotion, Doug Gordon, a safe streets advocate and co-host of the War On Cars podcast, walked to the front of the room and began reading the names of the five people killed by drivers on Ninth Street since 2004. As he was doing so, Halpern reached out and pushed him, then flipped off the crowd.

The 64-year-old, who also hosts a weekly meditation class at an Iyengar yoga studio near Union Square, told Gothamist that he didn’t regret his conduct during the meeting. “Yeah, I shoved him. It’s theater,” he said. “The majority of people in the room don’t live here. My suspicion is at least 40 percent are lobbyists or friends of lobbyists...You heard them cheering in unison." (Halpern himself lives in Inwood.)

A spokesperson for Transportation Alternatives dismissed Halpern's claims as baseless nonsense.

“Last night was not a serious discussion on solving Park Slope's real transportation problems, but a venue for a few toxic voices to blame and shame those killed on our streets while walking and biking,” said Danny Harris, the group's executive director. “They should be ashamed and all victims deserve an apology.”

For context, after hearing someone saying @TransAlt is funded by the associate of a pedophile and sitting through a 15-minute movie about DOT conspiracies, I decided to get up and read the names of four dead children and one adult who have been killed by drivers on 9th St. https://t.co/N1Ed6kN0ml — Doug Gordon (@BrooklynSpoke) September 26, 2019

Halpern eventually agreed not to show the second part of his film, though by that point, many people had already walked out in disgust. As Manning looked on with concern, Ralph Perfetto, the Bay Ridge District Leader—who lost his seat after he was convicted in 2011 for impersonating a lawyer, but regained the post last year—assumed the role of moderator. “I am here because apparently this meeting got out of control,” he bellowed.

Two officials with the Department of Transportation, as well as representatives sent by Congresswoman Yvette Clarke, Borough President Eric Adams, Assemblyman Robert Carroll, and Councilman Brad Lander, all sat silently behind Perfetto. With the exception of a brief assurance from Brooklyn DOT Commissioner Keith Bray that the city supported the bike lanes, but would listen to both sides, none of the officials spoke for the entirety of the evening, and most shuffled out early.

arrow Left to right: DOT Project Manager Preston Johnson, DOT Brooklyn Borough Commissioner Keith Bray, and a representative for Congresswoman Yvette Clarke's office Jake Offenhartz/Gothamist

The general tenor of the meeting did become marginally more civilized—or at least less violent—when Perfetto began rigidly enforcing a no cross-talking rule, calling on people to speak one at a time.

Those in attendance traded off between praising and condemning the street’s changes. A woman who lives on Ninth Street said the redesign made her children feel safer, even if she wasn’t happy about the elimination of some parking spaces. Jack Brown, who keeps the blogspot Coalition Against Rogue Riding (CARR), accused the bike activists of “praying to a false climate god.”

When a woman expressed concern about snow plows creating dangerous conditions come wintertime, a cyclist replied, “Usually that ends up in the bike lane, and we just kind of deal with it.”

arrow Myra Manning, alongside Ralph Perfetto, explains that cyclists ride too close to cars Dave Klasko

After several speakers claimed that the bike lanes were installed without community input, Eric McClure, who runs StreetsPAC and serves as the vice chair of Community Board 6, explained that the redesign had been unanimously approved by the body. And while the meeting’s flyer suggested that the changes would slow down emergency vehicles, McClure pointed out that the 43 feet between the bike lane buffers offers enough space for a fire truck to pass, even with two SUVs double parked adjacent to the existing floating parking spaces.

Opponents of bike lanes have long claimed that cycling infrastructure slows down first responders. But a recent report from the Mayor’s Office found that growing congestion and construction were to blame for a recent uptick in emergency response time.

“Those of you who are concerned about emergency response times, I’d love to have you advocate with me to get parking removed on one side of my block,” said McClure.

The two-hour event wrapped up with a lengthy monologue from Perfetto, who dispensed with his attempts at impartial moderation to claim that bike activists had “authorized” and successfully covered-up his friend’s death many years ago. “So there’s cause on both sides, if you look at this,” he concluded. “We need regulations for everybody—pedestrians, cyclists, and motorists.”

As attendees filtered out of the room, some of them still bickering on the sidewalk, multiple people said they were shocked by the behavior of their neighbors. By comparison, the Prospect Park West bike lane battles that once raged just down the block seemed almost tame, according to some longtime advocates.

“That level of craziness was just so off the rails, it makes me think it's the dying gasps of bikelash,” said McClure. "It’s clearly a generational thing. And that generation is going to disappear eventually."

Another participant, a Ninth Street resident who declined to give her name, offered her own succinct summary: “These people couldn’t organize a one car funeral.”

Correction: A previous version of this article incorrectly referred to Ralph Perfetto as the former Bay Ridge District Leader. The veteran Bay Ridge politician was ousted from the position by Kevin Peter Carroll after his 2011 arrest for impersonating a lawyer in his cousin's trial, but regained the seat last year.