GAY MARRIAGE ?: If Martin Luther, the Father of Protestantism, argued that marriage wasn't a sacrament...?

Good point. However, Luther did not discard it as holy. He simply shortened the list of sacraments in protection of Baptism and Eucharist, so as to set them apart by themselves as most holy of all. This did not change how marriage is regarded. It is still viewed in Lutheran theology as a holy covenant for one man and one woman.