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.

Sure it is possible. You can be neutral by banning nothing.

Or at the very least only ban something when the authorities literally force you to do so.

Banning nothing is fine if you want your community to die.

In theory, everyone has equal ability to share their opinions and all have equal weight. In reality, you have a lot less influence than someone willing to post 24/7 everywhere they can. The quickest way to drive away reasonable people is to do nothing.