Everyone, or at least almost everyone, acts according to personal interests. There's a whole branch of political science, Public Choice Theory, that deals with this. Where did you get this idea that altruism was common?

https://en.wikipedia.org/wiki/Public_choice

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lazyasciiart 44 minutes ago | parent [-]

How did you get the idea they think anyone is being altruistic? Usually the complaint that people won’t vote in rational self interest is suggesting that people are voting based on irrational evaluations of their self interest: for the benefit of their unlikely future selves.

	▲	pfdietz 26 minutes ago \| parent [-]
		Public choice theory explains why irrational collective results obtain from individual rational behavior. To get rational collective results requires that people act altruistically, favoring the collective over themselves.