Considering the animated discussions from a wide variety of positions, I'm not seeing what you are. I do see strong bias against overly aggressive and uncivil behavior. I also see a few members who have a hard time seeing beyond their own bias. It's natural to be more aware of behavior against your own "side". It's just one of our cognitive biases we need to be aware of and guard against.
Comment and submission data is available via the HN APIs. Put together an analysis and share your methodology and results. Regardless of your findings, I know I'd be interested in seeing them. I'm sure a lot of other HN members would be, too.
I pay pretty close attention. I browse with showdead on. Can you clarify what you mean by "don't show up at all"? Posts by banned users are dead as soon as they're posted, but I think you mean something else. Do you have a couple of examples of what you're talking about?