why did evolution build us to place fundamental emotional and normative value on conforming to what any rational selfish agent will figure out?

If you're running some calculation involving a lot of logarithms, and portable electronics haven't been invented yet, would you rather take a week to derive the exact answer with an abacus, and another three weeks hunting down a boneheaded sign error, or ten seconds for the first two or three decimal places on a slide rule?

Rational selfishness is expensive to set up, expensive to run, and can break down catastrophically at the worst possible times. Evolution tends to prefer error-tolerant systems.