The point is that the social consequences of a comment can be catastrophic. There is the potential to lose your job, lose your friends, lose your family. Even if your opinion was just miswritten, misunderstood, misquoted, outdated, or immature one can be attacked for seemingly random reasons.
Read some of the commentary on this thread, and note some of the well written examples that counter your comment: https://news.ycombinator.com/item?id=27581532