I see the point of this guideline, but will still argue that Circa provides more value to the readers here since it links out to multiple sources (also linked to SFgate: http://blog.sfgate.com/nov05election/2013/03/04/george-mille...), therefore giving readers a more holistic view of the story.
Please submit the original source. If a blog post reports on something they found on another site, submit the latter.