More Military Doublespeak

I'm either very naive or highly optimistic, but whenever I heard about "civilian contractors" getting into trouble in Iraq, I assumed that they were builders and technicians, the kind of people that you'd expect to be there during the rebuilding of a nation. I really didn't think that "civilian contractors" actually meant "mercenaries".
Is it just me that finds the idea of America hiring mercenaries to fight its wars a little odd?