The hymns Aigner lists are The Battle Hymn Of The Republic, America The Beautiful, and God Bless America. To the first hymn, Aigner asks how Christian could ever sing praises to war and rely on military strength for our salvation. To the second hymn, Aigner rightly laments over the idolization of America and an expression of faith in the American people. To the third hymn, Aigner questions the existence of any meaningful theology as well as the claim that America is a Christian nation that is a light to the nations. Aigner's retort is most appropriate; there is only one Christian nation in the world: the Church.
Aigner goes on to predict that America, like all other empires, will fall. And he asks could we really go on singing praises to our nation if Jesus was physically standing in our presence.
The second part of Aigner's protest declares what the Scriptures declare: that we cannot serve two masters. He goes on by listing the words of a hymn to show the difference between appreciating one's own nation and worshiping it.
Aigner's article is not deep, but it could not ring more true. However, there is another point that Aigner could have made which supports his contention. That worship of one's nation, in reality, is worship of oneself. This point is made clear by examining the religious reasons some Christians gave for supporting Jim Crow, and you could add for ethnically cleansing Native Americans from the land. The grounds for the "Christian" support for Jim Crow was the heretical belief that the White race was not just superior to the Black or Native American races, it included the notion that the White race was the chosen race. In other words, what those who used Christianity to support Jim Crow were worshiping was themselves, their own group. And if singing patriotic hymns around July 4th follows the same reasoning, then the singing of those patriotic hymns is merely another instance of us engaging in self-worship by praising our nation. And perhaps why refusing to sing praises to America or challenging its legitmacy angers some people so much is because to not sing America's praises is to rob those Americans of the worship they believe they deserve.