If 4chan cracked down on racism they did the worst job I could possibly imagine. You can’t even go to the fit or tv boards without running into literal, unapologetic, white supremacist views.
8chan if I recall formed because 4chan did away with /pol/ way way back for being too toxic to the rest of the site (it's meant to contain the scum, not breed it). 4chan eventually re-added /pol/, and 8chan, well, you know the rest there.