In reality how would we even know they are aliens? If you are an advanced race, you would have the technology to either hide your presence or affect the human identification in some way. If you didn't care if humans saw you, why not show up in Times Square? Why would you only show up in the US and only in ways no one but the military or government can see?
Does not follow Occam's razor.
Have you seen Star Trek? The federation exploration missions usually seek to speak first with the leaders and minimize their involvement with civilizations that haven’t matured enough. Not that they don’t still screw it up sometimes.
Too many variables for Occam’s razor to be applied to that question.
They could be as fallible as an emotional being might be and yet generally with benign, exploratory and diplomatic intentions as the federation in Star Trek.
They’re merely adhering to the “most powerful” government’s diplomatic requirements. You know, because they met the US first by chance.
There could be a good story in there somewhere...