HN is full of the dilettante type who consider themselves an authority on any field based on a few days of wiki-hopping.

I notice this every time I see comments on HN about a topic I actually understand in depth. Quite a few comments are just outright incorrect, most are misguided, but all are confident.

Yes, but a lot of people who are aware of their lack of understanding (or reduced understanding) actually choose to stay silent, or offer opinions with a lot of riders.

On the other hand, the most confident pronouncements usually come from people unaware of their lack of understanding.