>>18687171I think it'd be a bit of both.
/pol/tards would initially chimpout and start raiding other boards out of rage on a scale never before seen, rendering much of if not the entire website unusable for days, weeks or even months. But eventually they would get tired of this and disperse to other websites and/or No Rules boards like /bant/, /trash/ and /b/.
4chan would then slowly get better now that much of the cancer as well as the magnet attracting them was gone, but how much it would improve and how long it would take is hard to say.