You have to be a bit of an ego to say “I should be in charge of this whole city!” I think you have to be an even bigger egomaniac in order to say “I should be leader of the free world.” Politics aside, I’m looking mostly at regular people here. I spoke with some friends who are definitely not white but self-identify as white, and would be considered white by a casual observer. They said they do this because of the obvious advantages of whiteness, and the disadvantages accorded to those who signal they are other.
Of course, there are some differences between the races if you look at them on the macro level, and at genetics. Still, those differences are nearly as fluid as those between people of a single race, and so for the most part, become meaningless. This article really only looks at the “do I shoot this suspect or not” kinds of benefits afforded to white people.