Then we would have 20% fewer supporters. How is that good?
More people respect religious faith than you might think, and this has been a historical constant in America. A person who has a vision of something to believe in is going to be motivated to go somewhere. This differs from the person whose life is dominated by doubt or stark disbelief. He or she only wants to hand out wet blankets.
I think it would be folly to try to explicitly tie a conservative movement to a particular denomination, or even to require a viable candidate to be associated with a house of worship. But for them to explicitly encourage faith is not folly.
Atheists are almost all democrats, as few as they are, minuscule in numbers actually, but they do fight America and conservatism with passion and they have influence at the top of the left and media.
I don't know how you got losing 20% of the GOP from reading that post.