Its because they werent honest with their 1st wife to begin with they married someone whose against polygamy and hide it from her because that will ruin their marriage with her its cowardlyPolygamy is not haram so why do “Muslim” men hide their other wives from each other like a gaalo hiding his mistress from his wife. It’s because you know they won’t accept it so you lie to the mother of your children to give you some sort of human decency when you’re literal scum and a deceiver who can’t hold his wife’s rights.