3. The fact he would NOT be commissioned due to depression is NOT a factor?
I quote from the article
The 24-year-old told The Associated Press that a determination earlier this semester that he could not become an officer due to clinical depression
In simple terms, he has medical problems and the Army told him they do NOT want him as an officer. He has probably wanted to be an officer all of his life (including Grade School) and that decision was a blow to his ego, but to resign over that would NOT get headlines. On the other hand to resign over religion gets him support for his "position" from various groups and people on line. I suspect that is why he brought up religion, it received more on line support then his depression.