It isn't so much about our freedoms or our GDP, although they play a role.
Unlike China and Russia, we have WAY more guns and we're WAY less corrupt. That's a pinnacle of financial security; you can be confident that the United States will honor its treasury securities. China and Russia? Probably, except who knows what internal or external conflicts shake their fragile economies, and maybe they just won't pay out on time or at all.
People hate the fact that we spend so much on our military, but the inconvenient truth is that we have the comfortable lives we have now in large part because we have so many god damned weapons, and very advanced ones at that. That goes for those who live in foreign ally nations; deep down, their leaders know we will intervene on their behalf if shit hits the fan. America has had its share of fuckups, but they're still not eclipsed by the fuckups of Russia or China.