If you see a discussion as a debate instead of as a chance to listen to other people’s stories, how can you not get defensive? You yell and take up space and time in order to have the loudest voice and win your point. The object is to make the other person give up and knuckle under. Who wouldn’t get defensive?
From a more distant perspective, people get defensive because the discussions are really presented using the debating model. Point/counterpoint. Affirmative/negative. A forced duality.
If you think of discussion as storytelling, and everyone gets equal time, you see a very different kind of discussion. Talking sticks are useful to teach people how to behave this way. You learn to listen to the other person, instead of thinking about what you are going to say. In that way, asynchronous discussions such as this one are better. We can all take all the time we want to in order to listen to others. Then we can share our thoughts.
In this other kind of discussion (I’m not sure if there’s a word to describe it), people build on each other and respond to each other instead of trying to refute each other. Contradictory views can coexist, and people don’t have to defend them. Our goal is to understand how others came to hold the views they hold, instead of trying to convert them to our view.
I don’t like debates, and online, I tend to tune out from them pretty fast. The religion “discussions” often end up that way. I might participate once or twice, but often I stop after that. My questions are generally designed to get people to tell stories, rather than to give them opportunities to disagree with or attack each other. This doesn’t stop people from doing these things, but you can’t have everything.