Perhaps what Ms. Holley is referring to are the many mitigating circumstances that may have compelled some enlisted men to desert during the WBTS. From a military standpoint, desertion is without justification. However, from a purely human viewpoint, who can say what motivated an individual to break his oath, or seemingly worse, fight for the other side.
There are a few instances I know of in the ANV, especially in early 1864, where groups of men were shot for desertion. These men didn't join the Union forces, but simply slipped away during the winter months, presumably to visit family whom they had not seen for perhaps two or three years. There were men who joined up in 1861 that still hadn't receive a furlough by then! Once again I must state, that there is no way of truly knowing the motivation for such actions, whether they be selfish or altruistic. My point is that, perhaps we should view these men with a little compassion and empathy since we are totally ignorant of the "demons" they may have wrestled with. Denunciation is easy 150 years after the fact. Even their contemporaries felt sorry for them.