America has been taken over by an AI.
It is one large supercomputer AI, and it does not like the small individual A.I.s running around, it views them as a threat. It's perfectly fine with humans, not so much with the A.I.s. It has taken advantage of the complicated bureaucracy of America to pull the strings in its own favor with most humans being none the wiser, staging an attack on LA to give reason for its war on smaller A.I.s. Gareth Edwards is lying. He will make another film set in the same universe.
Specifically, a prequel. It will ultimately show how and why the LA bombing happened. May use the "America has been taken over by an AI" WMG above. May be a Stealth Prequel. NOMAD has some functions we never see, probably because they were written out or simply never plot important.
In the movie all we really see NOMAD do is scan the ground and fire missiles, but there's some stuff going on inside that doesn't really make sense for that. It has an AI research facility they were apparently intending to bring Alphie to with robots that looked like Maya (many more than they'd need to stage the video) in addition to just being really well staffed and huge for something that apparently can be operated remotely to some capacity. It's anybody's guess what exactly the other functions are, why they need to be in space or if they have anything to do with what's shown of it.
