I'm having trouble following the argument from your premise "it is a stupid question to ask why I referred to a chair as a chair instead of a
snkwoo" to your conclusion "it is
not a stupid question to ask why, when we have no answer to a question, we don't just say that we do have one".
The answer (to both of those questions!) is, of course, that we could do that, but it wouldn't accomplish anything. Asking the question just means you have no idea what you're saying. Or in other words, it's a stupid question.