To qualify, it needs:

- To have a negative net effect. Explosives for example don't qualify...

I was more idealistic about this kind of thing at one time, but it really is easy to rationalize the "Work on what you want to, don't worry about the end use" attitude that I have now. All I needed to convince myself was a good example.

Imagine that it's the early 1980s. Reagan is in office, the Cold War with the Soviet bloc is still very much a thing, and Star Wars is ramping up. Every other week it seems that somebody proposes yet another batshit-crazy weapons system. You're an engineer with progressive political views, and your bosses are asking you to work on a vast, global satellite network that will allow the military to locate both targets and assets with pinpoint accuracy anywhere on Earth. As far as you're concerned, ol' Ronny Raygun can fuck right off, and you tell them as much. "I'm not working on anything like that!"

20 years later, it turns out you missed your chance to get in on the ground floor of the most important public utility since the telephone system, all because you could only see the destructive uses for the technology.

For me that's hypothetical since I was nowhere near old enough to be employed at the time, but it's easy to say the same thing about applications like UAVs, autonomous vehicles, and ML/AI in general. CV is nowhere near enough of a defense-centric technology to justify refusing to work on it, IMO. Someone who refuses to work on CV on ethical grounds is walking away from their share of our technological future, just like the hypothetical engineer who refused to work on GPS.

We could put all sorts of weapons in the list, with nuclear bombs in a top position. But think about it. Hydrogen bombs didn't kill anyone. Although the idea is debatable, they may even have acted as deterrents, preventing conflict. As for Hiroshima and Nagasaki, it basically ended the war, who knows for how long it would have continued otherwise, with potentially more victims than what the nuclear bombing have caused. More generally, the most technologically advanced countries are now living in an unprecedented time of peace, despite having the most advanced killing machines ever.

I tend to agree with the general notion that nukes are a net win for world peace, but it's debatable whether the net death toll due to warfare has been that much lower in the post-Hiroshima age. Superpowers just conduct proxy wars nowadays instead of beating up on each other in person. If you added up the civilian toll of those proxy wars, it would probably be right up there with many WWIII scenarios, but since those conflicts are happening somewhere else besides major American or Soviet cities, nobody much cares.

The other concern I have is a relatively new one: people are going to forget what those things are and what they do. Eventually, the last person to see a nuclear explosion in person will die of old age. Long before that happens, morons with microphones will deny that Hiroshima and Nagasaki ever happened, just like they do now for events ranging from the Apollo landings to Sandy Hook. Others will take the position that nukes are just bigger versions of regular bombs, nothing that special.

So long term, who knows... maybe it would be better to put that genie back in the bottle if we could. Dunno, and in any case, it's hardly the same thing as CV. I can understand if someone is reluctant to work on nuclear weapons technology, but that understanding stops well short of refusing to work on CV.