If you can't understand why someone disagrees with you, you're at a big disadvantage when it comes to convincing them of anything on the topic.

This goes just as much for misunderstanding or simplifying their position. That does not instill trust.

Now - I should say that it's extremely understandable not to understand why someone disagrees with you. That is probably going to be the default condition. We'd better expect it. But because we'd better expect it, we'd better prepare for it.