The appeal of an online community is having members who participate in bad faith? That's an angle I hadn't expected.

Sure. Outside already satisfies good faith discussion. There is nothing gained in duplicating the exact same thing online. Use the right tool for the job, as they say. Online discussion is a compelling in its own right because you can stop being you and take on someone else's persona to try and discuss from their vantage point. This gives opportunity to understand another side of the story in an environment that provides the necessary feedback to validate that you actually understand another side. Too often people think they understand other angles, but one will also want validation, which online discussion provides. More often than not you'll realize that you actually didn't understand it at all, so it is a valuable exercise.