I am going to go out on a limb and say that "extremist" videos is just what they say they are going after. More like anything that tends to be conservative that is getting too many views.

https://www.cbsnews.com/news/youtube-extremist-videos-redirect-pilot-program-efforts-falling-short-researchers-2018-05-17/?ftag=CNM-00-10aab7e&linkId=51847380