The answer is that WHO doesn't assess health care quality; it assesses health care equality, exactly the way any organization on the Left assesses it. And since the world's and America's news media are on the Left, they report a Leftist bogus assessment of American health care as true.Yep. But this seems to be an example of Prager trusting his audience to condemn the Left without too much reflection. Because Prager certainly doesn't make any sort of positive argument about the benefits of American Health Care. He underlines two serveys that who America having poor healthcare and dismisses them as Leftist, but doesn't feel the need to make the counter argument.
I suppose because he can't; what Prager and his kind believe about the American Health Care system is that it's great if you have the money to avail yourself of it. And if you don't or are on a lower rent insurance package; one in which you are denied coverage regularly, well that's your own problem. Liberals and many moderates on the other hand judge a healthcare system, at least in part, by how accessible it is. We all share the same air, we all get the same germs. So it's in societies best interest to see that medical care is available to all.
There is a case to be made for what Prager belives; I think he's wrong but there is a case for it. But Prager fails to make this case because, essentially, he doesn't have to. Just elevate the dreaded left and trust his audience to make the right decision.