I believe he is dedicated to the Corps. He was and is adamantly opposed to rescinding DADT. Think about it. If he resigns, I guarantee Obama would assign a lackey as his replacement. If he stays in he can mitigate the situation, perhaps establishing a strict code of conduct which would enable any individual who steps the least bit out of line to be drummed out of the corps.
Good points. Fortunately, unlike the civilian and government world, our military leaders advanced to top positions from within the services. Amos could put Hussein in a tough spot by resigning. His replacement would be viewed as a lackey and without question would hurt the Marine Corps.