The article ends with "This article is republished from The Conversation". I'd guess it goes against "If a post reports on something found on another site, submit the latter." (https://news.ycombinator.com/newsguidelines.html).

> Where did you see it was banned from HN ?

I looked at the submission history and saw that ~all of them were marked as [dead], that's usually a site-ban then. (you might need "showdead" enabled in your settings to see that)