It used to be that extreme groups kept to themselves and were pretty quickly ostracized because of their extremism. Most people in San Diego wouldn't join Heaven's Gate, and the group wouldn't be able to spread very far because the further it reached, the more pushback it would see.
On the Internet, that isn't really true. There are always enough people who can be convinced of the merit of an idea, and so extreme groups continue to grow in size. As they do this, the overlap between any given extreme group and other groups grows, because the extreme group is growing. This means that their ideas metastasize out into the population as a whole.
Scientific racism, neo-reactionaryism, monarchism, even just defiant "political incorrectness" and "I'm no SWJ"-ness. The heightened availability of all of these ideas produces the same, as group polarization (a technical term in social psychology) happens on a scale never before seen. This is hardly limited to the right wing; liberal-identified Tumblr users are more behaviourally restrictive than most of the anarchist-communists I knew in college, even though the "safe-space" rhetoric of the current liberal milieu originates from more radical activist circles.
Expect to see more scientific racism on hacker news; hacker news is a fundamentally more friendly platform for racist and misogynistic viewpoints because women and people of color are so underrepresented and the focus on "objectivity" and "data" mean that a shoddy study that is the very essence of scientific racism can beat out the stories of however many women or PoC dare to speak out, only to be shouted down.
Most of the people making these comments would probably be fairly reasonable had you both been born 20 years earlier (or possibly later, if the world grows more sane) and met at a party. Few people set out to become a scientific racist, they just see an article linked (possibly by a Stormfront member, who knows) that "just makes sense to them"; they believe it and internalize it; when they see future statements they are more likely to remember those they agree with and forget those that disagree with their existing outlook; gradually, they become more and more "awakened" to the "racial reality" of the world until finally they're posting on Neoreactionary News about how they've finally realized democracy is degenerate and women should never have been allowed to vote.
