I regularly get emails from people with legitimate, even thought provoking questions who feel a need to apologize for them. Usually it is something like "Sorry if this question is silly."
No seriously asked question is "silly." I don't care if we're talking religion, politics, physics, or cooking. You can't get the answer if you don't first ask the question. Even if it is a "beginner's question," beginners still need to ask them! People are afraid that questions make them look dumb. They don't. They make them look serious.
I will not go so far as to say that there are no silly questions. I consider "How much does Canada weigh?" to be a fairly silly question.