Your omission of which subreddits specifically is notable. Please, tell me why the site's reputation, community and society as a whole is improved by enabling r/niggers with a platform.
Though in general, I would say Reddit does benefit from allowing lousy subreddits. Not because those subreddits are good things. But the policy of allowing easy creation of subreddits is also what's made Reddit good. There are plenty of great niche subreddits.
Once you get into quality control, it's going to reduce the potential for the creation of good communities too. You also need a lot more admins.
Well, yes, that was my point. However, that particular subreddit has been reincarnated as another I have no particular inclination to name. As yet it's unbanned.
By banning that subreddit, and creep pics etc. the admins have already made some broad stances on what is or is not acceptable. Banning them as the reemerge can not be, I imagine, such a huge task as to require multiple people.
