Ours is a nation where the unimaginable has somehow become inevitable. If Mr. Chou, Mr. Tran and Mr. Zhao committed mass shootings, they did so not because they were Asian but as Americans. Mass murder may be the fullest act of assimilation possible into a culture that has proudly chosen as its colors the red of innocent blood, the white of panicked eyes and the hazy blue of semiautomatic smoke.