The bare minimum that God asks is that a person acknowledge Him as God and to be thankful. The inability to do this means He has probably removed your ability to respond as a penalty for trifling with Him.
At the very least, the example of some snot-nosed brain actually embracing such an inane position should serve as a stunning refutation of Intelligent Design.
Perhaps, though the following is little more than informed speculation.
George E. Mendenhall, Frank Moore Cross, and others have emphasized the centrality of kinship rights and covenants among the proto-Israelites. In fact, the traditions reflected in Deuteronomy were comparatively egalitarian, with strict rules for dealing with kin, servant and slave. In a period of arranged marriages and a religious insistence on sexual purity (i.e., virginity), only the girl child, of young virgin, would be seen as appropriate for integration into proto-Israelite society. To the extent that this is true, the exception made for virgins reflects, not a society intent on rape, but a society intent on taking into itself only those who could be treated 'equitably', i.e., in accordance with the law.
Of course, all this talk of slaughtering the evil Midianites is little more than jingoistic propagande, but even propaganda must pay homage to the realities and constraints of the society in question.