It seems he hasn't resigned (presumably he could only do that if so invited). Stars & Stripes story 29/08/2021 :-
The video does not appear to be a resignation in a formal sense, though he says he plans to follow whatever the service’s legal requirements are.
The 'legal requirements' cover a multitude of sins of course, leading if so ordered to the convening of a Court Martial, subject of course to the Exigencies of the Service.
Scape Goat, Martyr? You pays your money and makes your choice.