Smacking down is not necessary, beter moderation is key and the solution. I just think this experience gave you a golden nugget to have a better answer next time , thank you for sharing, we also had a jerk on our meetup but we already received a signal he would attend at forehand, so we managed to conclude some actions in case things would escalate

Indeed like @grayruby mentioned the best way to moderate this kind of behavior is to refer to questions and discussions after you finishes your talk. To make it easier it would be Nice to have somebody with you that moderates the interaction with the public so its easier to keep it clean and simple. Or make make a list also with possible behavior and counters reactions . 🙏🍀 good luck with all your beautiful adventures 🚀