What Nam means is that if the Christian apologetic who wrote that article truly believed that God were to command believers to commit genocide (murdering entire populations, down to infants and babies) today, they should do it. Their rationale is that God is perfect, therefore anything he commands is innately justified. Worshipers don't even have to think about it, because God already did.
He also came up with the tiresome misrepresentation of atheism/skepticism/liberalism as being based on nothing but personal preference, whereas God is 'objective' and therefore anyone who acknowledges an 'objective' standard is implicitly acknowledging God. Frankly, this isn't even good sophistry.
Basically, this is the tactic of the apologetic - rationalizing away the actions of God in the Old Testament to give Christians the justification for obeying a god who countenanced the slaughter of innocent children due to purely arbitrary standards of morality. In short, the Hebrews did not act based on some perfect moral standard, they acted based on their own standards which they attributed to YHWH.