***I will respect the opinion of a General who resigns in protest of a policy. When they stay until retirement....***
I'm not sure what you mean by this.
Every General Officer I am aware of has been in at least 22 year (and they very few and far between, very rare indeed) IOW, since every General has been in for at least 20 years, every General can retire. Even if the "resign," they retire.
I mean resign in protest and speak out then, not wait until they think that they have maxed out on promotions.