“Why USA is the only major country where no voter ID is required?”
Because the dominate of the two national parties claims the largest minority in the country (13%) is too stupid and ignorant to be able to obtain photo identification. They have convinced the dominated weaker party that is it racist to even ask for ID.
But not too stupid to apply for food stamps, Medicaid, rent subsidy, get free Obama phones, aid to dependant children, pass drivers licence test, etc etc.