Two thousand years ago people were at each other's throats over "homoousion". One thousand years ago over "filioque". Four hundred years ago it was predestination. The idea that large-scale conflict over ideology is some kind of aberration to be explained by "biases" is just a figment of the modern ideology of "rationality". In five hundred years they will study this time period and ask, how could they have been so worked up over these minor and obscure points, hardly even comprehensible any more, that they tore their society apart? And the answer will be the same as always - human nature: superstitious, tribal, dogmatic, and violent.