The military industrial complex is a huge employer, both in the state of California and the rest of the county. The likelihood of enough people saying no to a high paying job like this is effectively zero.
And even if - wave a very large magic wand - every AI/ML engineer in the United States pledged to not work on military applications, the U.S, would just contract that same work out from the U.K., Canada, etc...
There is a limited amount of total work that can be done by those people. Every low-level employee who refuses to work on this decreases the overall capacity. Every manager who has to deal with recruiting new people and getting them up to speed reduces capacity. Every company with reduced ability to compete for bids reduces capacity. Pushing the work to foreign companies and getting more red tape involved reduces capacity. It's not zero.
And even if - wave a very large magic wand - every AI/ML engineer in the United States pledged to not work on military applications, the U.S, would just contract that same work out from the U.K., Canada, etc...