Contrary to what you may think, the mere 'single issues', as you derisively term them, go to some of the worst crimes committed by humanity against Christ the King. It's important to those who fear and love Our Lord. The Faith matters to them, if not to others. A Protestant faith of sorts mattered to our founders. It was important to THEM. It was even foundational.
Yes, they are important to those who fear the Lord. But as you certainly must know, most serve another master. Not all "conservative voters" are believers....remember?