To a large degree you can't choose how the DoD or other letter agency uses what they buy from you. Obviously you can set some contractual guardrails but realistically if you build drones that can mount hellfire missiles you have to know that it can be misused by some 22 year old. Its tempting to believe that software is different, but once its on-prem its out of your hands.
The difference is scale and accountability. Surveillance tech is impacting everyone and is part of every kill chain but its not what people see so there is very little accountability for it. Building a drone that launches something has far less scale and far more accountability since its effects are visible. I personally think there is a big difference between being part of something with at least some accountability and limited scale compared to unlimited scale and no accountability. Of course many people would disagree and set their levels lower (mine are actually lower than this now) but I think that DOD contractors can think in at least this level of terms and decide to be apart of some things and not others in a meaningful way. No matter what though, a problem being hard isn't an excuse for throwing your hands up and saying 'I'm good because the DOD says it is ok'