A belief can survive because questioning it threatens a relationship around it.

Some convictions are held in place by people rather than by evidence. To doubt them aloud would put a friendship or a family table at risk, so the doubt stays unspoken and eventually stops being thought. That is not stupidity. It is a quick calculation about what you might lose, made so fast you never see it happen.

If a belief of yours feels strangely unexaminable, ask gently who would be upset if you changed your mind. Naming them does not mean leaving them. It only separates what you actually think from what keeps you close to people you love.