Certainly not all (and in my record collection, hardly any, and then only in compilations). But singers with a political message tend to get more attention - let's face it, they'd be failing if they didn't.

"There are those who make things happen, those who watch things happening, and those who ask what happened." Seems to me that too many political songs are written from the point of view of the third group, complaining about the actions of the first.