So everybody online can be dismissed, except the people posting online that everyone who posts something online can be dismissed? How does that work?

https://news.ycombinator.com/item?id=42371412

It's everywhere. You're simply wrong. Sort by date, sort by score, look on any broader news story and check out the comments. They're not "extreme", either. Even if their content was, which it isn't, it still wouldn't be extreme by definition at this point.

The point isn't to dismiss everything outright, it's simply cautioning that online commenters are a tiny minority of the overall population, and if you see a surprising opinion showing up in the top comments, you shouldn't extrapolate that everyone holds those views.

This only holds for opinions. If someone posts a link to a survey that says out of a representative sample of Americans, 70% of them support abortion or whatever, you should believe that (assuming there are no issues with the organization conducting the survey). Same with other forms of argumentation. You shouldn't distrust the top answer on stackoverflow just because it's from 1% of the population, although you probably not think the average person is some sort of expert on every programming question either.

Sort by date, no difference. And FWIW so far I only heard the idea that this CEO deserves empathy online