I think that what he is saying is that you can use your anger to motivate yourself. You see this kind of thing all the time in sports, right? You get some guy from one team saying something bad against the team he's playing next. Or a sportswriter says something bad about a team. And all of a sudden they're all motivated because they're angry.
What Stockdale is saying here is that if you get angry, you have to use it to motivate yourself. You cannot just let it burn inside you and make you unstable and weaker. Instead, you need to use it as motivation.