>Would it make more sense to instead target the patterns used by predatory commentators rather than shutting down the system completely?

Terrible, terrible idea.

Transfer this to the "real world", and see how it plays out - let's build a system that will analyze people's behavior and penalize them on whether it classifies them as pedophiles or not! This will surely protect the children.

Moderation is a notoriously tough problem even without the whole trouble of automating it through something as "ephemeral" as content analysis.