Muslims permitted (not necessarily encouraged) polygamous marriages because in ancient times, many Muslim men were lost to war leaving too many widows with children. A Muslim man is not obligated to support any woman who is not his wife so the men took on more than one wife. The ruling was no more than 4 wives and they couldn't be related (sisters, children of the wife(wives), aunts, etc. The women had to be of sound mind and able to make decisions for themselves, were not to be coerced or forced into marriage. The marriages had to be witnessed and made public...not done in secret.
My second marriage was a polygamous one. After my first traditional marriage (when I was Christian), which lasted only 3 months, I knew that "traditional" marriage was not for me. I used to say I'd never marry again....ever. But my 2nd was one of the nicest people you could meet, the handsomest man I'd ever seen and I finally fell for him. A good mutual friend had tried to get us together for years but I said I wasn't interested because I knew he had a wife. We wound up getting together in our own time on our own terms due to some unforeseen circumstances (one with a paranormal element). I held off for three years before finally marrying him. I knew the stigma attached and didn't know anyone else (at the time) in that situation. I met some people in Virginia who were in polygamous marriages and found out later that the Sheik who married us was too. My husband, my co-wife and I were in the same age range when I married him...47-48. We were married for 25 years.
Polygamy has been demonized by the reporting of men who have so many wives, many of which are minors. Also, if those families are a drain on the state funds (getting public assistance), that is certainly a catalyst. I had read a book, by a non-Muslim author entitled Man Sharing. Not only Mormons and Muslims practiced it, historically Jewish people practiced it as well. And as previously mentioned, it was no biggie back in Biblical times. Men had hundreds of concubines. This country is somewhat hypocritical too. Men who have mistresses are often excused and even admired. Affairs are so common in this country. But when someone legitimizes the relationship via marriage to a second (or 3rd) woman, he's seen as evil and possibly faces jail time. Add to that.... alleged religious freedom gets taken off the table.