I think a lot of people in tech work on really questionable projects that create huge social ills, then talk about "Well, at least we don't build weapons!" -- ignoring that when measuring human suffering, their unrestrained manipulation and exploitation causes much more than weapons of war do, in practice.
So when unqualified, I tend to hear your argument as simply trying to hide the messiness of what you do, rather than than it's inherently more ethical than building weapons would be.
tl;dr: I don't believe the military is less ethical, I think they're just more honest about what they do.