To me, polygamy makes more sense than homosexual marriage.
Exactly. In polygyny(one man to two or more wives), at least a child might be conceived whose father and mother are married to each other. That would never happen in a same-sex union since(obviously) neither of the two “husbands” or two “wives” can naturally conceive a child as a result of the “marriage”. Of course, such a common-sense view of reality is probably considered a “hate-crime” nowadays.