The problem is not with Christians, but with disciples of the Devil. I believe that the bible makes reference to followers of Satan coming to deceive and speaking in the name of Jesus. So what does Jesus say about prayer. Well he says several things, as in what to pray, and how to pray. But in Mark 6 he says to not pray in public. In fact he says to go into a closed and close the door. Prayer is to be private. No exceptions. Thus we can conclude that if one is directly acting counter to the teachings of Jesus that he must be an agent of Satan. So when we come across this: "In the first instance, Chaplain Lt. Gordon James Klingenschmitt was court-martialed from the U.S. Navy for praying in Jesus’ Name at a ceremony at the White House while in uniform in 2006. Since then, it has taken a special act of Congress to preserve the right of military chaplains to pray in the name of the Lord Jesus Christ, but Chaplain Klingenschmitt was still not reinstated." So, yes, when someone acts contrary to the words of Jesus we should keep such agents of Satan out of the military.