There is a school of thought that recommends “moral” people doing “immoral” work because if those people left then other “immoral” people will take those jobs and more readily implement “immoral” features. So the “moral” engineers have an incentive to stay and act as a front line against “immoral” actions, or at least have an insider’s position for whistleblowing.
Military drones are here to stay, and whether or not the US builds them, other military powers certainly will.
Ultimately, I don’t think this changes anything.