same way no alien will intervene....
the question of alien intervention seems a simple one indeed. if aliens have developed technology that spans allows them to travel the universe, based on what we know there is no conceivable reason they would need to intervene in our affairs.
I cant think of any reason at all they would need to. they would not need oil for energy, to eat us for food, to occupy our planetary space.
one assumes easily that a technology that achieves space travel at speeds beyond anything we know would first have solved a whole of their problems that would include starvation and all the nonsense we yet grapple with.
such solutions would also have long included for them social relations in which they were prisoners of personal and group wealth, exploiting each other to death for such material possession and social control.
they would have long come to an acceptance of themselves for who they are, collectively solved their material problens and into the universe looking for eternal answers.
relatively humans would be putz, violent, nasty and ignorant. they would scan this planet from a million miles away and be gone in a blip..totally uninterested.
they would not want to save such a species as we from ourselves. can some one give one reason why humanity must be save from itself....