It's pretty common on the Internet and on HN too, and in public debate. Aggressive, confident assertions deny others the power to disagree.

Contempt and shame - super-popular rhetoric these days - achieve the same thing, and they are related (both kinds of rhetoric are an aggressive display of arrogance). They assert, implicitly, that there's no way to debate this person.

Anger is another similar tactic.

Then if you don't understand that it's tactical, you give up. So far, to my amazement, very few people seem to understand it; almost all take it at face value.

Perhaps, but all I'm doing is reversing the equally unjustified claims in the parent. Ironically they've lamented unjustified claims in the sibling comment to this one, but their post is chock full of them.

How are you supposed to know that they're unjustified when the (at that time) top comment is just "no"? Are you supposed to accept the superiority of some anonymous commenter, or is the fact that they just "need to" post "no" and therefore show that their opinion must be superior?

I was that commenter who said no. I was replying to equally unjustified assertions. Just because my reply was shorter, does mean it contained fewer justifications.

No.