Stachel was in fact Heroic
As depicted in the movie.
Of course in the novel he is depicted as an alchoholic, and in the movie he is opportunistic sometimes to the point of endagering his squadron and the accomplishment of its mission.
But he fought for Germany, and not some pathetic notion of chivalry, or false nobility. His job was to shoot down, and kill if unavoidable, Allied airman.
That's the truest fact of war. His heart was true to that. Too bad the movie had to play up the sordid political aspects. Not that it made for bad drama, but that was by far secondary to his obligations.
He came from the infantry, where hundreds of thousands, millons, died in the mud trying to do their duty, many even while hating it to the core of their beings, and futile and without honor or glory.
Shame on the nobles who fled to neutral countries with their golden nests while leaving behind the millions of true soldiers who gave all they had, or nearly all.
Typical West European melodrama.