It may have allowed polygamy as an act of mercy, but it also mentioned many wrongs of Israel. The fact that it mentioned wrongs is not evidence of approval.
The prophets often mentioned that, because Israel chose to worship Baal, many curses was pronounced on the state of Israel. Polygamy may have been one of those curses because we know today that polygamy often makes a society more violent because it leaves many males without hope for a mate.
In today’s modern world, with jet airplane and ship travel, how could “many males” in our society be left without hope for a mate? There are four countries I can think of, right off the top of my head, that contain HUNDREDS OF MILLIONS of females willing to marry a Western male and no, Russia and the Ukraine are not on that list.
Interesting speculation.
Regards,
In any case. Polygamy is more Biblical than shame homo-marriage.