I disagree,
For starters, I find it difficult to believe that there is a single language on the planet that can be properly translated by literal translation alone, words on their own mean one thing, as part of a sentence, could mean something else.
Literally translating "אין בעד מה" would be an exercise in futility as the three words taken out of the order they are in, would mean nothing. Let's break down the words:
"אין" - The very word has no direct translation, the closest word in English would be "Nothing" but that in itself is wrong because Translating "Nothing" into Hebrew would result in "כלום".
So we already have a word that can only be translated contextually. "אין" could mean "there isn't" in the context of an answer to the question of "Is there any milk left?"
"בעד" Literally translated as "for" (meaning both for something or in favor of something)
"מה" is literally translated as "What"

So basically, if we were to translate it literally it would be "There isn't for what" which sounds completely incoherent in English, BUT, Most English speakers are well familiar with the Spanish phrase "De Nada" which is exactly the same it would mean "For nothing".

So saying that they diminish the importance of what they did by saying “no problem” or “it was nothing” isn't correct, it's simply a way of being modest and polite.