I think his point is that there are no modern medical treatments or drugs developed anywhere outside the US. And of course, we all know that's the truth.
Or at least "truth-like".
As Colbert points out, for certain microcosms of mentality, it feels good to believe. And there are a number of for-profit concerns that make a lot of money by feeding beliefs like that. The US, after all, is a very special place. Far more special than anywhere else - so it must be true, because it feels so good, like a gun in the hand.