For one, I agree that the justification for wars, and in general, the idea that "we have a war going on" is important for them to reiterate.
People need to know that there is always a threat from some other side of the world, from ideas foreign to our culture. It's like it was in the cold war.
I don't think anything was "planned" here. There is this thing called "emergence", and having such events as this shooting, emerge, is expected, especially with all the images, videos, and stories of bombings and terrorism that we keep seeing daily in the media. People tend to copy things. The shooter couldn't rationally handle his realization of the real foreign policy agenda, the deeper plans that go beyond "liberation and democracy".
Is there a possibility that the intelligence services may have been aware that Hasan would go on a shooting rampage? One can't exclude this possibility, but if I had to guess, I would think that surveillance systems and A.I. software that may predict such cases in the future is not fully operational yet.