The justification gets worse:
*** w09 7/1 p. 30 Does God Approve of Polygamy? ***
To counter the attacks, Jehovah repeatedly sent his prophets to warn his people when they veered from righteous standards. However, he knew in advance that his people would often fail to obey even the most basic of commands, such as the one against idolatry. (Exodus 32:9) If they would struggle to obey so basic a law, how would they fare with a law against polygamy? With his perfect grasp of human nature, Jehovah saw that it was not yet the time to forbid that practice, which was already long-established in those days. Had he done so, Satan would have found a very easy means of seducing Israel into sin.
God’s temporary toleration of polygamy had other advantages. It helped the nation to grow rapidly. The larger population helped to ensure the nation’s survival until the time of the Messiah. Polygamy may also have provided a measure of protection for some women, giving them shelter and a household in dangerous times.
Due to their imperfection God's people cannot even keep basic laws so how could they keep the law against polygamy. Surely, bringing this up-to-date. God's people are even more imperfect so how can they keep the law against immorality, which is already long-established in these days. Jehovah still has a perfect grasp of human nature so why would he chose to forbid this practice. In doing so, Satan has a very easy means of seducing JWs into sin.
God's toleration of polygamy had other advantages. It helped the nation grow rapidly. Likewise today by tolerating immoratlity think how many more JWs there would be and around 30,000+ less disfellowshipped ones each year.
Polygamy may also have provided a measure pf protection for some women. Likewise today. Better is it that a JW woman commits immorality with a fellow JW than go off with someone in the 'world'.