They should. I don't have a problem with polygamy. Again, that is about other people's relationships, not mine. As long as the people involved are consenting, key word being "consenting", I don't give a shit.
Polygamy has historically been a huge problem because women didn't have rights. Well times have changed. Women have the same freedoms as men do. So, if 10 women want to marry one guy, then go for it. If he can please them all, he is a better man than me.
Your religion has programmed you to want to control what other people do. even when the things you want to change doesn't hurt anybody.
This all amounts to basic human empathy with compassion. You know? The concept that I wouldn't want somebody doing it to me, so I won't do it to them.
That is the ONLY FUCKING RULE ON THIS PLANET THAT I FOLLOW!!! I don't follow the law. I could wipe my ass with paper that our laws are written on. I could wipe my ass with the original manuscript of the bible. I don't need a book to tell me how to live or what is right. If you need a book to help you figure out what your morals and ethics are, then you probably have no business telling other people what is right and wrong.
Do you want somebody telling you who you can and can't marry? Fuck no, man. So, stop doing it to other people.