The guidelines ask HN users not to post shallow dismissals because of the effect they have on discussion: they make it even more shallow and dismissive. Look at what an offtopic subthread we got below.

People always hold forth on things they're not expert in. That's humans being human. We can't change that. What is possible is for those who know more to share some of what they know with those who want to learn. Doing that leads to much better discussion.