To understand why, you must first realize that Islam is not just a religion rather it is a way of life. This is why Islam has a built-in welfare system and pre-cautionary safe-guards. God knows that men have a higher desire for intimacy, they like to have more children and a wider company of wives. In societies where polygamy is not allowed, men take the re-course of pornography, prostitutes, extra-marital affairs etc.
In all these cases women are being treated as sexual commodities. There is no accountability and if in case of the mistress where emotional needs of women might be being met, that relationship is often based on deceiving other women, taking from her rights and a mistress can be thrown away and replaced instantaneously. Also, there is no limit on how many mistresses you can have no how many prostitutes you can visit. By women opting for polygamous marriages, they become someone’s wife, they are treated honorably, and they are loved equally.
Not according to the Torah, The Bible or The Quran. This is because a vast majority of the prophets and messengers also had more than one wife. It was in the Quran that God limited the number of wives per man to a maximum of 4. Therefore, Polygamy is not a sin to God.
The most documented person in history to have the most number of wives is Prophet Solomon “Sulaimaan”. He has been mentioned in the Quran, the Bible, and the Torah as having had around 690 wives and give or take 290 concubines. His wives included the Queen of Sheba, many foreign princesses, and women of Moab, Ammon, Edom, Sidon and of the Hittites.
Yes, the Quran allows but under certain conditions, As Per Surah 4 (An-Nisa), Ayah 3: “Marry women of your choice, Two or three or four; but if ye fear that ye shall not be able to deal justly (with them), then only one”. Beyond this, we know that Islam is the only religion that limited maximum concurrent wives to 4.
Actually, polygamy in Islam was never about maintaining an equal ratio of women and men. The exact reasoning is unknown and left to the infinite wisdom of God. What polygamy in Islam does is help those men who have a desire to take on multiple wives and want to have larger families. Subject to them meeting the criteria set by Allah of equal treatment between his wives. This allowance for men is also considered a form of social care for certain women who otherwise would be marginalized or sidelined. Such as widows, divorcees who may have children already, women over a certain age, women who may some sort of disability etc.