Liberals, progressives and secularists (LPS) have not no substantive reason to oppose polygamy, do they? Of course not!
It can’t be for moral reasons because LPS have demonstrated their moral allegiance is to themselves, and not to any higher law than themselves. Just like a moral-less society has shifted its mores from traditional marriage to some sort of acceptance of same-sex marriage, this will occur also with polygamy. Some dismiss this suggested movement just like many years ago same-sex marriage acceptance was dismissed.
“Mr. Chamberlain” has a signed document asserting this will not be the case!
After that bestiality.
On what moral grounds with LPS group oppose? They have none.
Evil abounds with LPS; they are faithful servant of their master (2 Cor. 4:4).