"When somebody gives you a peek behind the curtain while chatting, you don’t go and demand proof."
It is up to you as a communicator to establish your credebility so that people can trust your words and take your seriously. It's not a favour to the audience.
As far as I can tell, this gentleman has categorised you as a random dude at the bar making things up.
Let’s apply that here.
Guy at the bar is telling war stories, you aren’t sure He is telling the truth, sounds like a tall tale…
You never served in the army so you’re not sure… But your gut is telling you He is a liar.
What do you do?
Nothing. Because you are not in a position to know better. It’s your unsubstantiated guess against a possible lie.
If you are coming to the conversation in good faith, you don’t start with an accusation of lying. You share your doubts and ask politely for more information.
It is up to you as a communicator to establish your credebility so that people can trust your words and take your seriously. It's not a favour to the audience.
As far as I can tell, this gentleman has categorised you as a random dude at the bar making things up.