- Downvoting creates echo chambers,
- No accountability for moderators.
I think the downvoting should be removed completely. Downvoting is basically giving people the power of a mini-censor and the people love it.
Subreddits can be completely censored by moderators and there's no way to know this is happening. Maybe reddit can develop a way to judge the behaviour of the moderators. Like showing what posts they removed, for example.
I've been part of plenty of internet communities that don't become like this. Even completely public forums and IRC channels. I guess HN isn't as bad as reddit because we have an above-average intelligence crowd, but there are some opinions I am careful not to mention here as well.