The FDA, ruling body of all things edible, has decided for us, that we are incapable of cooking our own food or not being smart enough to not consume rotten meat & dairy. So they insist that all dairy is "pasteurized" to prevent contamination by some hypotetical germ that may or may not actually exist. The downside being that pasteurized milk makes awfully bland tasting cheese.
So yes, american cheese's are terrible.