/pol/ has been this way for more than half a decade now. The blame is shared by the influx of the election tourist newfags from Trumps first cycle and m00ts selling the site to Hiro who installed a faggot that calls himself rapeape as moderator.
https://www.vice.com/amp/en/article/m7aap8/the-man-who-helped-turn-4chan-into-the-internets-racist-engine