well, when you find someone who clearly admits (not just says something that leads you to assume) that the
sole reason they are against homosexual marriage is because their religion says such a relationship is immoral, then feel free to call them out on cherry picking.
Thing is, that lots of people are not very good at seperating out the different reasons why they are against something and are not very good at articulating it all clearly. Just because someone uses a generic argument or doesn’t go into an in depth reply, or isn’t careful to make it clear that their opinion is not solely based on the immorality of an act according to their religion doesn’t mean that they they therefore have no reason apart from the immorality of the act to be against it.
Pretty much everyone who is against it thinks that it is important for society to have a special incentive set up for people to have kids in loving, safe, and stable envrironments. This has nothing to do with whether or not homosexual relationships are considered moral by the church and everything to do with a rational consideration of what social and legal structures are good and/or bad for society. Trust me, there are more like me than you think.