I've been working in the aerospace (now space) arena my entire career, and there's a lot of overlap there with the defense industry. What I've seen is that it's very easy for people to look at their work as a narrow area and to forget about the consequences of it (how it's used, what it actually does when used). I think many (I won't say the majority but it wouldn't surprise me) in the defense and intelligence sector don't think, either willfully or because of lack of introspection in general, about these things.

Very well said. I will provide an analogy.

Imagine I came to know that ghosts exist with supernatural powers. My first reaction shouldn't be of fear. It should be of curiosity. What laws are prevailing in ghost realm which provides them with great powers over material world. Does one becoming a ghost suddenly know the truth of Rieman Hypothesis or P=NP?

The same could be asked of people who are supposed to know better by virtue of them close to knowledge and technology. Should they spend their improving lives of others or enslaving them for material gains?

Smart people are very prone to using their intellectual abilities for self deception and rationalisation.

Never underestimate the lengths and depths people will go in the name of a salary.