When someone is arguing from a position of strength, they don't need to resort to petty jibes. You are already arguing from a position of strength. When you a

When someone is arguing from a position of strength, they don't need to resort to petty jibes. You are already arguing from a position of strength. When you add petty jibes, it weakens your perceived position, because it suggests that you think you need them, rather than relying solely on your argument. (As a corollary, you should never use petty jibes. When you feel like you need to, shore up your argument instead.)