Basically saying that the antigay marriage folk need not be only focused on that aspect of marriage and that they also mention divorce amongst other stuff. So this avenue of thought doesn't seem as productive as directly addressing why gay marriage should be a thing.
Some bring up the flippant nature of the current gen and rushing into marriage and not treating it with the respect it deserves. Divorce would be a result from that. The reasons for divorce would be the issue for some. Such reasons leading to a high rate.