But even judges attempt to be neutral. There are law/rules and you attempt to judge every case/comment based on that. As a moderator, I don't simply delete comments because they don't fit my political views -- I'm capable of that and so are most other people.

That's entirely different from people that are explicitly not trying to be neutral and are trying to promote a specific political ideology. I expect that majority of moderators on Reddit are not trying to promote anything. However there is definitely a growing contingent that don't want neutrality and they are taking over.