Relying on a community to police itself is great for an open community (like /r/gaming), but if you want any kind of formal structure you need some moderation. Especially on such a sensitive subreddit as /r/twoxchromosomes where the potential for abuse, spam, and general hatred is so high. Although with that community, I seriously have to wonder why reddit would want it to be a default, or why the moderators agreed. Terrible, terrible decision to take a community of respect and trust and open the floodgates to the greater internet full of assholes and trolls. Oh well.
Voting in an open system only works to reenforce the viewpoints of the majority of voters, not the viewpoints of the specific community. That's why I can't vote in the elections of another country.
This already exists: each user has a "show karma breakdown by subreddit" link on the profile page for exactly this.
I assumed that reddit admins made /r/twoxchromosomes a default because it was a good subreddit and wanted to expose better content to the default users.
Also, I thought that subreddit moderators don't have input regarding whether the subreddit is made default.
Spam and hateful comments fall pretty fast anyway, but that doesn't mean that it should stay there. What would you prefer - a youtube page with all comments and some hidden due to a low score, or a page with all the shitty comments removed altogether? Someone is going to see that shit anyway and it's going to be awful as it involves everything from rape threats on support threads to someone that is trying to post something completely irrelevant to the subreddit.
And then there are comments that are really unpopular but they aren't hateful or spam, and even if it's buried we don't remove those. They would be mixed in with the hateful comments just because people don't like what the person is saying.
Some type of moderation is, in my opinion, a necessity. There are very few free-for-alls on the internet - if you have a good example of that working out, then I would like to know.
We have 1.1 million subscribers in an active and default subreddit. Related and private subreddits are growing too to meet the random niche demands of some of our users, and that's a great thing. Our users have options if they don't like our moderation style.
And, it's worth nothing that HN is a moderated community, and while there are people who find that problematic, the reality is that a significant portion of the best contributors here wouldn't stick around if it were not reasonably moderated. I believe that's true of communities in general, but particularly communities that are controversial (I'm a mod at /r/occupywallstreet; I've seen some shit).
Precisely because, as alexis said (https://news.ycombinator.com/item?id=8390156) reddit is a platform for communities as much as it is a platform for users, and the norms for communities are created through moderation. The moderator gets to create the community they want, and it's up to users to accept the standards of moderation or move to/start a different community
As for tagging, it helps in some situations but its not an universal solution. The UI is kind of lacking (you need a 3rd party extantion to hide unwanted tags and it doesnt filter posts in the reddit.com frontpage) but it also doesnt do anything for passing users who havent configured their tags.
In a hypothetical world maybe its possible to create a smarter "hotness" algorithm that is less prone to these problems but in the current system I really don't think "just downvote the bad stuff" is a practical solution.