I keep meaning to write something about this, but: There are two kinds of "why". One is "I understand what you want but I think it's stupid so I'm going to argue with you." That one is insufferable. The other one is "I don't understand what you want, and I need more information to know what to do." That one is inevitable.

Unfortunately the line between the two is very fuzzy, because every request is underspecified, and we fill in the gaps with context and guessing. And everybody has a different threshold for how sure they want to be that they understand the request, before they go off and implement their best guess about what it's asking for.