1. The generals are backbones of the nation. They prop up the military prowess of USA with great leadership, expertise, morale and allegiance.
2. Pete Hegseth is an ignorant, imprudent former major, knows nothing but to fawn on Trump. He was designated as the Secretary of Defense utterly for his indiscriminate loyalty to Trump, instead of the country. He is serving Trump personally at the detriment of the interests of the country. He will face the consequence after Trump moves out White house.
3. The generals cannot forbear the humiliation, unwilling to behold a clown tarnish the honor and luster of Ministry of Defense. Besides, they are incapable of doing anything to halt that. Therefore, they choose to resign and leave.