Why has polygamy been discouraged in some places and encouraged in others?

When people begin to place too much emphasis on one aspect of a teaching, then its true place has to be re-established.

For example, Islam gives women the right to seek khul‘a [divorce] for any reason; she is not required by Islam to justify her reasons to anyone (Fiqh Ahmadiyya, vol. 2, p. 87).

Now if people started discouraging divorce, to prevent broken families, by saying that a woman can only divorce if she can justify her genuine reasons to the qadi [judge], then we would have to correct them. We would have to re-establish that a woman has the right to divorce her husband even if she simply dislikes him (Sahih al-Bukhari, Book 68, Hadith 24), and the qadi has no right to deny her request. Even if a certain divorce would hurt the husband and children, and although the wife should be advised against it, to preserve her basic right we would still affirm that Islam does not require her to justify her reasons to anyone.

The Promised Messiah ^as addressed many of the extremes that people go to in opposing and supporting polygamy and taught moderation. He ^as said that to marry again for the sake of becoming lost in physical pleasures is a sin. On the other hand, he ^as also said that to marry again for the sake of Taqwa is not only allowed but a means of reward (Tafsir Hadrat Masih Mau‘ud, vol. 3 p. 216). He ^as said that if a good-natured man wishes to marry again, but his wife vehemently opposes the very teaching of polygamy, then he should marry again to punish her (Tafsir Hadrat Masih Mau‘ud, vol. 3 p. 213).

On the other hand, he ^as also said that if a man’s wife is extremely saddened, for personal reasons, by his taking a second wife, then if he can sacrifice out of kindness to her, he should not marry a second time (Tafsir Hadrat Masih Mau‘ud, vol. 3 p. 216).

He ^as gave specific circumstances in which polygamy becomes necessary (Tafsir Hadrat Masih Mau‘ud, vol. 3 p. 204).

On the other hand, he ^as also said that men can marry up to four wives “at the time of any needs or expediences of theirs (Tafsir Hadrat Masih Mau‘ud, vol. 3 p. 213).”

He ^as encouraged the members of his Community to marry again so that by having more children, the Jama‘at would grow. On the other hand, he ^as said that men should not abuse Islam as an excuse to become lost in physical pleasures (Tafsir Hadrat Masih Mau‘ud, vol. 3 p. 218–219).