does the person in question have to be an officer?
Topic on Talk:Colonel Kilgore
Considering that Sociopathic Soldier is described as "The grunt version of Colonel Kilgore", I'd say this trope needs to be an officer, yes.
I don't think that comparison always fits. Type 3 of Sociopathic Soldier explicitly hates war. I don't see type 4 as really enjoying it either.