The reason "Christians" or any other group of followers of organized religion care what you do and how the government is run is because they are trying to control you. Just as the author of this article is warning of the "godless" trying to control peoples mind he is calling for "Christians" to force their ways on others. Oraganized relgion is mind control. Organized religions cause atrophy of the mind. Their goal is to make you one more goose stepping solider in their army of mental (and physical) conquest.
Also I found it quite funny when he tried to argue Darwinism was a religion. Philosophy maybe but not a religion. It doesnt even attempt to address the spritual aspect of humans how can you consider it a religion.
Though in the end this is all irrelivent as Muhammad was the last prophet of God.