No, Munger declared literally in the past that his best quality is to be «rational» and one of his best known recurrent expressions is, "you will agree with me, because you are smart and I am right".

I’m not disagreeing that he says that or that some people apparently find that endearing. It’s just hilarious to see it written out as an earnest sincere response.

Munger himself mention the thing while joking in public. For the rest, I am not sure about what you find hilarious, if the ground sincerity of the statement makes you react. Some are just confident.