This is an example of Parasite SEO. You get a site with high Authority site that you can put some content on (HN/Reddit/Medium/Steemit/GetJar). Then you send a lot (100k+) spammy backlinks and then rank for some difficult terms.
Google doesn't penalise big sites for spammy backlinks compared to a fresh domain, and also with the high authority, it will rank a lot quicker.
A good way to find example of Parasites is to search "Fortnite hack". I can see links from LinkedIn, Steam Workshop and a PDF hosted on a hacked (presumably) website for a roofing company.