...there's more and more evidence showing the way people think when they are confronted with antithetical voices and arguments. If people are seen to be opposing what someone holds close to them, the critical thinking portion of their brain effectively shuts down. People are very good at rationalising what they hold dear. Smart people will parrot poor arguments and reason when it fits in favour of what they believe - just look at what passes for Christian apologetics, some very smart people have written absolute dreck - and will dismiss legitimate criticism when it goes against. Psychological studies have shown that once a belief becomes ingrained that showing contrary evidence can even increase the certitude that people will have in that belief. You can change how people will assess arguments by the affiliations you attach to an argument. In other words, we have every cognitive reason in the world to not try to give those who disagree with us a fair hearing.
It's all the more reason to show that you understand where the other people are coming from, and to be able to take these issues and be able to talk clearly and resolutely on them. It's what should be expected from people who are meant to be coming from a knowledge-based position. Link