Syria and Rwanda more peaceful than the US and Russia?

http://www.visionofhumanity.org/gpi/news/24/us-and-russia-ranked-among-least-peaceful-nations/

This bit particularly caught my eye:

"The low ranking of the US, which comes below Syria, Rwanda and Mongolia, reflects its high level of -military expenditure and engagement. It also has proportionally more citizens in jail than any other state."

You can see the rest of the rankings : http://www.visionofhumanity.org/gpi/home.php