We've previously discussed the meaning of a downvote on meta, and I think that's worth reading before discussing anything further here.
I don't at all like that perfectly reasonable questions (especially from people new to MathOverflow) asking about acceptable behaviour get heavily downvoted. It's discouragin, and pretty rude --- no one is going to cleanly differentiate between a downvote meaning "the answer to your question is no", and "you shouldn't have asked this question".
There's no quick solution, as we shouldn't make rules about how people vote on meta. Here's a proposal:
On questions with clear yes and no answers, rather than downvoting the question to indicate no, give a short answer "No, you should not insult leprechauns on MathOveflow", or vote for the existing short "No" answer.
(Of course, the original poster could also provide two or more alternative answers themselves, if they are implicitly asking for a poll of opinions, rather than advice.)