Interestingly, they CAN appear in uniform in photos associated with their positions as directors of Christian organizations like Officers Christian Fellowship, of which I’m a member and in whose quarterly (or so) magazine, Command, I regularly see what look to be official military photos.
FWIW, there is a moral imperative for commanders to mandate Christian exposure of their personnel on active duty.
Unlike other scenarios in a free society, a military establishment mandates immediate obedience to orders from senior ranked officers and line officers in combat 24/7.
The commanding officer therefore, has incurred a responsibility for his juniors to insure they are provided with an opportunity to be provided the Gospel if they are unbelievers and an opportunity to receive proper pastor-teacher guidance as believers while they are serving under the command of others.
Both the gift of pastor-teach and the gift of evangelism are spiritual communication gifts given by God the Holy Spirit to certain believers. The spiritual communication gift of pastor-teacher is given to a person to spiritually discern the appropriate part of the Word to be taught to the believers in his midst per God’s Plan, so that they are in the right place at the right time to perform by His Plan.
Likewise, the spiritual communication gift of evangelism is given to some believers to communicate to unbelievers.
Unlike the common citizen who incurs the responsibility to find his own pastor-teacher and continue obediently in faith through Christ in his daily studies, the military serviceman, is also under the legitimate authority of his commanding officer to obey 24/7 the orders of his seniors.
Likewise, his seniors bear the responsibility to God to insure pastor-eachers are made available to the serviceman for their spiritual growth, only possibile through faith in Christ through daily intake of Bible doctrine by their appropriate pastor-teacher.
Recent ecumenical perspectives fail to recognize the significance of God the Holy Spirit in the continuing sanctification of each and every believer, every day and moment of their lives. Many worldly officers believe they are able to substitute a worldly system of counterfeit belief independent of faith through Christ and still advance in good works. Such thinking is good for nothingness, not only jeopardizing the sanctification and spiritual growth of their juniors, but also placing their commands at risk of divine discipline, being in the wrong place at the wrong time on the battlefield which is deadly.
IMHO, if our commander-in-chief was remaining in fellowship through Christ in all things, he would relieve those in the chain of command who seek such counterfeit substitutes to God’s Plan and place the US armed forces at risk, without divine guidance through faith in Christ.
That is interesting. Maybe it's because OCF (of which I was a member also, way back when) restricts its membership solely to the military, and so there's no danger of an appearance of a military endorsement?