This is Paul from Human Interest. I'm a co-founder of the company and wrote the job post in question.
That job post was intended purely as a statement of our work culture. Our only goal in posting it was to attract the sort of folks who might enjoy working within that culture.
It's worth noting that there's a lot of cultural diversity between companies in the tech industry these days, and there are some in which "10x engineers" might thrive. And that's okay! We just wanted to find a way to catch the attention of people who might be a good fit for us.
I think a big part of building a company is deciding what you do (and don't) stand for. For example, Gusto, a company that we greatly admire, did so by saying that they were "not hiring hackers" (https://gusto.com/company-news/gusto-is-not-hiring-hackers). Again, there are plenty of companies that are.
YC kindly provides us the platform to advertise job postings on Hacker News, and doesn't allow direct comments on those job posts. I'm glad you posted this here on HN, because it gave me an opportunity to better explain where we're coming from.
Does that make sense? Let me know what you think -- I'm happy to chat more about this here or directly by email (paul@humaninterest.com).