The goals for a chatbot assistant are to be useful, correct, and not insult people. The goals for a defense AI are to extract correct features, provide useful guidance, and not kill the wrong people. If you are working in defense you already have a belief that your work is morally correct: most of those justifications are either that your work will kill bad people more effectively, and so save friendly lives, or will pick who to kill most correctly, and so save innocent lives. Having an AI that is better aligned towards those goals are better.
You may disagree that working in defense is ever morally justified! But Palantir dont't share those beliefs, and want to do as good of a job as they can, and so want the most aligned AI model they can.