OP is radically incorrect regarding where US parties would fit on a global scale. There is actually a lot of good research out available in political science papers based on large-scale surveys conducted over decades that show the US parties to be close to the middle of the right and left respectively. If you removed health care from the equation (given how messed up this is in the US) then the two parties would actually shift a bit to the left when compared to right and left political parties in other western democracies. The past five years or so may have muddied the waters slightly with the impact of populism, but prior to this point they were not significant outliers.