Reddit didn't ban them. It took so much racist crap for TheDonald to get wiped, and even then, the same assholes just made a new sub and continued on with dogwhistles.

Reddit also seemed to allow right wing brigading while punishing leftists in a very unbalanced manner. Multiple "moderate" (sane, non-tankie) left-wing subreddits had to close around major US political events because alt right chuds would swarm them and the admins didn't help. Meanwhile I once got a 30 day ban for "brigading" when all I did was going to a right wing post that was linked on a progressive sub and engaged in what I saw as good faith debates - and they were actually productive as I've received multiple comments from right leaning accounts about how I provided new perspective. No name calling or anything, actually civilised debate (which today seems impossible), around universal healthcare and education being something that benefits everyone in a society, even if indirectly...

Then the whole thing turned to shit around 2018, and by Jan6, things got incredibly polarised, making debate impossible.