AITA for loudly correcting a rude guy in line at a fast-food place?

This happened years ago when I was 22, but it popped back into my head recently and now I’m wondering if I was the jerk.

I was on my lunch break at a fast-food restaurant next to my job and a convention center. The place was packed with people from the convention. Behind me in line was this short man wearing a smoking jacket and a name tag that said “John.”

I glanced at his name tag and said, “Hi John, are you here for the convention?”

Without even looking at me, he smugly replied, “It’s Mr. Smith.”

Something in me snapped. I used my stage voice and said: loud enough for pretty much everyone, including what I assume were his colleagues. “Sorry, I don’t talk with a*holes.”

He turned beet red, left the line, and didn’t get his food.

It felt satisfying in the moment, but I’ve always wondered: AITA for calling him out like that, or was he asking for it?