I don't think this is a good marker for intelligence, but I think if you avoid dismissing issues because other people are dumb you will generally think harder and in the end will have a better understanding of the issue.

I have a personal rule that goes along the lines of "If I can't explain why a smart and kind person thinks the opposite of me it means I don't really understand the issue". It doesn't mean that I have to agree with them, but I always try to understand where they came from.