As I see it If you fall above the center line you believe some people should control other people. You believe you (or someone in authority) know what is best for people using a gun or the guns of government is the best way to get people to comply. That is why Hitler and Stalin are way above the line.
If you fall below the center line you believe people should be allowed to decide for themselves what is best for them even if that means they make poor decisions.
left right: I'm not quite sure but I think applies more to above the line