It rings true but as with many things that seem intuitive it's an illusion.

Hacker News doesn't have opinions. Individuals on Hacker News have opinions. Different sets of individuals comment and vote on different threads. There's zero reason to suppose that it's the same people expressing both ideas or even that it's the same people voting on those ideas. To the contrary, I've spent enough time on this forum (way too much time) to know that there are whole sub-communities on HN that overlap very imperfectly. We self-select based on titles, topics, and even on time of day.

The only thing this kind of logic is good for is producing fallacious arguments dismissing someone's opinion because someone else holds a contradicting opinion.