No, really, there is no such thing as a stupid question.
Just off a conference call where even a simple question raised good answers.
If the question can bring about answers, discussion, or even more questions, then it wasn’t in vain. If it starts something, starts people thinking or talking or just starts anything, then it did its job: it asked a question.
If you knew the answer, maybe you wouldn’t have asked it. Maybe someone else didn’t ask a similar question, but you did so that helped them. Maybe they couldn’t formulate it well (maybe you didn’t formulate it all that well either!) but you got it out there, you tried, you started, you began the conversation.
In the conversation, the question might get reworded, reworked or even reprimanded (!), but it started the conversation and if nothing else, it might incite another question.