Personally, I think the censorship happens in a pretty biased way. There is still a lot of very problematic content in places like /r/The_Donald that just gets let slip because there are so many users and the mods are very influential. Other political subreddits like /r/socialism however, even if they have a lot of users, will get treated much more harshly by site admins if they are ever reported.
Similar things happen with discourse on facebook and twitter, where calls for ethnic cleansing by white people are often overlooked, while angry posts by people of colour that offend white people will get deleted or get users banned. It's really no wonder that US politics has gone the way it has when there is so much McCarthyism embedded in the moderation of these public forums.
I think it's a matter of perspective. The BBC here in the UK aims for roughly equal complaints of bias from both the left and right, and reddit seems to get the same (e.g. /r/altright and /r/leftwithsharpedge both getting banned). I've seen complaints of both overzealous and permissive moderation by admins for all types of content which leads me to think they're actually reasonably balanced.
Similar things happen with discourse on facebook and twitter, where calls for ethnic cleansing by white people are often overlooked, while angry posts by people of colour that offend white people will get deleted or get users banned. It's really no wonder that US politics has gone the way it has when there is so much McCarthyism embedded in the moderation of these public forums.