You're asking for a much more intense "quality control" kind of moderation that is one of the reasons Reddit is sinking. That's asking for a lot more mod actions, which is a lot more time spent moderating, and also results in some degree of subjective application of rules for "quality". Heavy mod workloads and subjective decisions tends to drive good, well-balanced mods away (they have actual lives to lead with less time to mod) and only attracts the shitstains with nothing better to do who mod for their own personal power.

Downvote a comment if it isn't contributory. That's what the button is for (not a "I disagree").

Edit: also many of those one word answers spawn a lot of good discussion underneath them. So they're not always totally worthless