This is NOT on you. If the "public speaker" was rattled that easily then he needs a new line of work.

When you deal with the public, you have to be able to keep your cool. If you can't stuff like this happens. It was his own fault, OP.

"While you were writing your novel, did you know that I was fucking your wife? No, seriously, Linda has a small birthmark on her inner thigh two inches to the left—"

Unless you were a jerk trying to be "funny" I don't see how it's your fault at all. And even if you were a jerk, you still didn't make them do anything. But if you were a jerk, don't be a jerk.

What was the question that you asked him? That's what I want to know!

Don't blame yourself. If he works as a public speaker, he should be able to keep himself calm and present himself in a professional manner. It's not your fault if someone who has chosen a very people-centered career can't deal appropriately with people.

Obviously, the author didn't know as much about his own subject of expertise as he thought he did! lol

waiting for the follow up

Not your fault, OP.

On some level we'd all like to think that we're powerful enough to control others, but the fact is that HE snapped. I don't rule out the possibility that you provoked him, and maybe you're just not a nice person. But the final responsibility for what he said or did is on him.