One thing that often shows us and our ‘opponent’ that none of us understand as much as we think we do is to take the ’explain how would that work test’.
When you want to question someone’s opinion on a complex policy, don’t ask them to give you reasons for why they believe as they do - it only makes them defensive and often they stick to their beliefs even harder. Instead ask them to explain in detail how the policy would actually work in reality to accomplish the desired goals - how it step by step could be implemented - the steps and mechanisms involved in getting it done.
And also if they have thought through other effects. This often makes us all realise that we don’t understand as much as we think we do.