I mean, I'll take a stab at it... the electoral college can be argued from first principles if you consider that the U.S. was supposed to be a federal union of sovereign states. There are certainly reasonable arguments for federalism and devolution of power.
The U.N. doesn't directly elect the general secretary.
The US is not, in practice, a union of sovereign states today, regardless of whether it was in 1789.
Is that an argument against the electoral college, or an argument for re-devolution of power? Because the latter is probably easier to do than getting rid of the electoral college, given the requirements to pass a constitutional amendment.