People might be less open to questioning certain things, because those things work well for them, and they work well because they aren't questioned. There is an adverse selection for questioning them.

For example, let's say everyone in your society has an arranged marriage. The marriages produce children who then get arranged marriages themselves. This keeps the society going by providing a steady supply of new people. If someone starts to question it, they don't get an arranged marriage, and don't have any children. The questioner does not get promulgated.

(Note this is not an argument for or against arranged marriage. There are obviously many ways to arrange society and raise children.)