If you'd bothered to read the original Merriam Webster article, you'd have found you are incorrect:
"Parsing the expression, we have a joining of two negatives: no means "not any," and problem implies a difficulty in accepting something. Someone so inclined could deduce that a reply of "no problem" implies that one might have had a problem or difficulty with the task but in the end that wasn't the case, and for that reason only they're happy to have obliged."
From the article.
The article is wrong. “I did not have a problem” is a single negative. And no thr problem is not a difficulty in accepting something, it is a difficulty in accomplishing something. “That thing I did for was not difficult.” Single negative.
Thus we prove that anybody who has a problem with “no problem” is really just a whiny idiot who can’t even understand simple English.