Twitter reportedly won't use an algorithm to crack down on white supremacists because some GOP politicians could end up getting banned too - Business Insider:

A possible algorithm that could allow Twitter to more effectively crack down on Neo-Nazi and white supremacist content could report and suspend accounts of Republican politicians, Vice's tech news site, Motherboard reported...
https://www.businessinsider.com/twitter-algorithm-crackdown-white-supremacy-gop-politicians-report-2019-4