Is press freedom relative?

This post links to a story from Reporters sans Frontieres which ranked the U.S. 17th in the world in press freedom.

We were beat by Canada (#5) and Costa Rica (#15). I think part of the reason for that might be not so much that we have less press freedom, but other differences.

For instance, would Costa Rican reporters or editors be willing to write a highly damaging expose of their government or a major corporation? If their natural inclination would be not to do something like that, and they usually write less controversial stories, then I think their perception of what is a free press is not comparable to the perception of U.S. reporters.

For both Canada and Costa Rica, there also isn't that much dirt for reporters to write about as there is in the U.S. Also, I'm vaguely familiar with the controversy regarding the gag order in this Canadian trial.