1. The President is not subject to the UCMJ because the military is under civilian control. Willie is a civilian. Willie is the Commander-in-Chief of the military because he is the President.
2. The military is wrong if they do not salute him. Period. The UCMJ, MCM, and tradition require respect to the office.
3. I resolved this for myself while I was still an E-3.
a) For officers I despised, I saluted and addressed the rank, eg. "Good Morning, Major".
b) For officers I respected, I saluted my superior, eg "Good Morning, Sir." or "Good Morning, Ma'am."
c) One rather retarded, dangerous egomaniac Captain actually asked me why I called him "Captain" and not "Sir". He asked - I explained. "Captain is an acknowledgement of grade. Sir is a sign of respect, Captain."
Yeah, I got in trouble. But I weathered the storm and it was worth it. The Captain was so dumb he let the troops know what I said. It just tightened us up, made us even more "ship shape".
4) The military must acknowledge the President. They can call him, "Mr. President" and totally avoid use of terms of respect such as "Sir".
Just my 2 centavos.