It may not hold true for scripted, time-bound, many-to-one events like talks, but for person-to-person interaction, people see nuance and context more easily, and it's harder to walk out of a conversation because we'd be losing significant credibility in doing so.

That might be fine on Twitter, where no one's going to bother looking through your post history, but again IRL, people aren't randomly looking around for other people to get into arguments with in the first place.