Being the best at deploying violence is how you defend against the chaos elsewhere. This isn't about "evil corporations" or misguided intentions, it's about human nature and how there will always be someone somewhere willing to cause harm. The only way to defeat them is by being better at it, but with the appropriate judgement to make sure its in proper defense.
AI has already been a part of warfare for decades and the value of anything other than being the best is rapidly diminishing because of the exponential advantage that modern technology produces. You either stay ahead or lose the war before it's ever begun. Given that choice, I would much rather have the strongest military with all available resources and talent rather than worry and hope the rest of the world stays friendly, until the day it isn't.