The dark void of ideological thinking has rarely been more evident than in the celebrations after the assassination of Charlie Kirk. Even committed leftists were horrified to witness the sheer relish expressed online from those who seemed oddly eager to advertise their lack of basic humanity. The ugliness was still evident last week at the University of California at Berkeley. Turning Point USA — the organisation that Kirk had founded and helmed — held an event on campus, in defiance of those who gloated over his death, that would have been the final stop of the college tour Kirk was on when he was killed.

I was invited to appear as a panellist for the evening, along with the comedian Rob Schneider, the atheist philosopher Peter Boghossian and the Christian apologist Frank Turek. We had an enjoyable time fielding questions from the audience and discussing our shared commitment to liberty despite our many other differences. It was, as expected, a jovial and good-natured exchange of ideas.

Outside, things were not so serene. Protesters had gathered early, threatening attendees and obstructing them as they tried to enter the building. While backstage, I was shown footage that was being shared online of pyrotechnics being ignited, glass containers being thrown, attempts to break through barriers, and attendees scattering as a car was apparently made to backfire to create the illusion of gunshots.

Although the speakers inside at the event unanimously emphasised a commitment to nonviolence and open dialogue, the mob outside appeared set on menacing anyone suspected of being a ticket holder. One Turning Point supporter’s necklace was snatched by a protester, according to police — he was later charged with assault and robbery — and a bloody brawl ensued when the victim tried to retrieve his property. In a video of the incident, you can hear someone gleefully calling out, “You’re bleeding, White boy.”

A distinction must be drawn between the throwing of glass objects and the punching of attendees, and the otherwise peaceful but obnoxious behaviour of the protesters. Those who assembled to chant “f*** your dead homie”, exalting in Kirk’s death, were perfectly entitled to do so. It is reminiscent of the tactics of the Westboro Baptist Church, whose members picketed soldiers’ funerals to goad their grieving families. But one cannot help but wonder: how could a moral compass become so irreparably broken?

Most of the protesters appeared to have misinterpreted the Turning Point event as a fascist rally. A group calling itself the “Revolutionary Student Organisation” had unfurled a large banner that called on the like-minded to “drown fascism in a sea of resistance”. Some self-proclaimed “anti-fascists” berated police officers. “Kill yourselves,” the officers were told. One protester yelled: “You have a gun, use it wisely.” A flyer was distributed by a group called “By Any Means Necessary” encouraging allies to “end fascist Turning Point’s youth-oriented campaign of incitement to violence”.

It is difficult to know where to begin with such fantasists. If they wish to take issue with the key tenets of Turning Point — free-market capitalism, limited government, national pride, individual liberty and Christian values — their case would be stronger if they addressed its actual priorities. Simply reimagining mainstream conservative principles as modern fascism is rhetorically feeble and historically illiterate.

Fascism was a uniquely evil creed of the early 20th century: it demanded a one-party state, the silencing or slaughter of opponents, ethno-jingoism and the worship of the state. The term is so often misapplied that it ought to be retired, but it has become too useful as an all-purpose political cudgel. In this Manichaean dreamscape of heroes and villains, accuracy is unlikely to prevail.

My experiences at Berkeley left me feeling a sense of hopelessness, that we are dealing here with a form of hysteria that may never be quelled. How have we reached the point where armed police are at all necessary at a discussion event at a university? How is it that 1 in 3 US students believe that violence is sometimes acceptable to silence a speaker on campus? Why are so many content to occupy a make-believe world in which free speech is detested and Nazis are goose-stepping in every shadow?

The thought kept crossing my mind as I sat onstage with Rob Schneider, whose cinematic back catalogue is far closer to the Marx Brothers than Triumph of the Will. At one point, while Frank Turek and Peter Boghossian were chatting amiably, it struck me as refreshing to hear two people with such antithetical world views relishing the chance to converse. There was not a fascist in sight. Had any actual fascists been invited to speak, I would have had no interest in appearing.

One self-proclaimed antifa supporter at least made the effort to engage in dialogue. During the Q&A section of the event, he walked to the head of the queue and directed a sneering question at Schneider in which he accused him of being “retarded”. (Don’t these people prohibit “ableist” slurs?) His cause would have been better served had he attempted a more forensic and level-headed criticism, rather than immediately surrendering the intellectual and moral high ground. But at least he wasn’t throwing bottles and punches.

After attempting some genial sparring with the angry young man, Schneider came around to the most effective approach. He walked to the edge of the stage and held out his hand. This appeared to alarm the extensive security staff guarding the stage, but it was worth the risk. After some deliberation, his detractor took his hand and Schneider said: “I wish you all the best. Thank you. God bless you.”

It was a powerful moment, and a reminder that — despite the hysteria of this interminable culture war — we are all going to have to relearn the art of conversation and debate.

• Andrew Doyle is the author of Free Speech and Why It Matters and The New Puritans