Omar Mohamad, 65, known as Uncle Omar called his victim “filthy” and “a creature” during the six-minute tirade in Hyde Park on October 6 2019.
He ranted that his rival was “worse than a terrorist” because of his sexuality and accused him of “spreading AIDs”, City of London Magistrates’ Court heard on Wednesday.
The victim, who is a convert to Islam, had alleged Mohamad was glorifying terrorism in his speeches at Speakers’ Corner, which prompted the verbal attack.
The abuse was filmed at the site, which has been famous for its public speeches and debates since the 1800s, and posted on YouTube.
Kalsoom Shah, from the Crown Prosecution Service, said: “London’s Speakers’ Corner has had a proud and longstanding tradition of providing a space for debate. But this does not mean it is a safe space for hate crimes.
“Mohamad carried out a personal attack on the victim based on his sexuality. Mohamad’s words were homophobic, hostile and designed to intimidate and discredit the victim, who was left feeling extremely upset.
“I want to thank those that called out this nasty behaviour at the time, and all those who provided statements to help the prosecution.
“Hate crime has no place in our society and the CPS will robustly prosecute offenders. I hope this conviction gives other victims of hate crime the courage to come forward.”
Mohamad , of Reading, was convicted of using threatening, abusive, insulting words or behaviour to cause harassment, alarm or distress following a one-day trial at City of London Magistrates’ Court on Wednesday.
He is due to be sentenced on September 22.
The CPS said it would be applying for a “hate crime sentence uplift” in the case, which can result in a harsher sentence for people who display hostility towards a person because of their presumed race, religion, sexual orientation, transgender identity or disability.