I think there's definitely a lot of noise. Having categories (or tags) would be a good aid to sorting through it all.
I don't see how not having tags helps anything or anyone. It just keeps the article space flat instead of organized by topic.
Of course, the articles still have different topics. They're just not easily distinguishable from one another by automated means.
Tags are bad because keeping the article space flat keeps out people with only marginally similar interests.
The article space is flat right now, but that hasn't been enough to keep the site pure either.
I think the battle for purity has already been lost. Now it's just a question of whether the site is going to be rendered useless because the number of submissions is going to be too great to slog through with a flat article space, or if it's going to be made manageable with tags.