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.
I would expect that in almost any tribe throughout history, females could be classified into the following categories:
The principles that many females would have a sexually-exclusive bond to exactly one male, many others would aspire to do so, and everyone would know who was bound to whom, are almost universal and can be observed even in tribes which have never heard of Western religions. As such, they cannot be reasonably described as a product of Western religious bigotry. On the other hand, vocal religious people who focus on the religious issues and ignore the secular basis for marriage make it easier for homosexual activists to dodge the fundamental secular issue which is that the term "marriage" was introduced to describe the union of a female to exactly one male, and thus a homosexual union simply isn't a marriage.