One thing that's worrying me that isn't covered here: a lot of this low-quality SEO content is constantly regurgitated to produce... low-quality SEO content. Content farmers use content from Google results to write content for Google results. Google is getting devoured by loops like this.

I'm not a native English speaker, so at one point I was trying to find an authoritative source for an old idiom... and the entire first page were all different websites regurgitating the same inaccurate text! They did no independent verification of their own.