Twitter absolutely safe-harbors the extreme left. I think it's the only tech company I would refuse to work for due to their moral failings.
[1] https://en.wikipedia.org/wiki/Priyamvada_Gopal#%22White_live...
[2] https://www.theguardian.com/education/2019/mar/20/cambridge-...
Edit as reply due to posting limit: It wasn't meant to convince you the KKK shouldn't be banned. It was only meant to correct the misleading implication that opposing the KKK is as "left" as Twitter gets.
(Scare quotes around "left" because I don't believe there's anything inherently left about "white lives don't matter". I.e. one can be a radical leftist without believing that.)
That said as much as I think that that professor is a door knob that should’ve been fired instead of promoted I also don’t think that she has nearly as much impact as the fucking leader of the KKK on social media.