The thing about federated comment feeds is that these news outlets will not be incentivized to embed them directly to their website, as they lose control of the content. This problem will damage the exposure that a federated system would receive.
I imagine people could delegate moderation responsibility to people and organizations with a strong reputation. Let's say GNU, EFF, and Larry Lessig would all publish moderation data and metadata; as well as your "friends" on various social media sites, friends-of-friends, etc.