This is, by the way, largely equivalent to the "Political Compass", and bears a certain resemblance to the "World's Smallest Political Quiz" or "Nolan chart" of libertarian propaganda.
The notion of dictatorship as a property right suggests a useful third axis: concern for political equality. This seems to weakly correlate with opposition to state coercion, although not entirely.
Not surprising. David Brin deliberately used the "Nolan Chart" as inspiration, and the link was a speech given to a meeting of the Libertarian party...
This is a great article at Aeon magazine. The author argues that the new ideological dichotomy is going to be between people who have great faith in technology and human innovation (Up) and the people who believe that humans are much more tied to their biology and the Earth (Down).
LW of course is a very Up community.