That is an interesting asymmetry. With death devices, the unlimited ceiling is more about the amount of deaths per cost, and other more subtle things like preservation of surroundings, etc. But, resisting the urge to go further down that rabbit hole for the time being...
Yeah, I really have no idea how to approach or measure this. Like, obviously to me, if someone is directly developing weaponry that they know will be employed against Iran, they're pretty much a jerk. But is the barista at Starbucks at jerk? Starbucks is a pretty bad employer and if only everyone would just not work for them for a little bit, they'd go right out of business. Both employees in both scenarios can have a dislike for the deeds of their company, but the weapon developer is clearly more accountable.
I think it just depends on a ton of specific situations. Like in this exact example, I can say that the weapon developer is a position that's much harder to replace, so the argument of "they just find someone else to do it" truly isn't as probably true as it is for a Starbucks barista. The weapon engineer also understands that their weapon is much more intrinsically harmful - that is, while it's true that Starbucks is a messed up company, a coffee company doesn't necessarily need to be messed up. But an arms company, well, I mean, you need those too sometimes (WW2 obvs), but it's a lot closer to doing harm in general.
I think it's kind of one of those things like judging your friends about having subscriptions to shitty services... You just kind of have to accept that everyone does what they can. Like maybe Alice cancels her Amazon subscription, but keeps her Spotify subscription, and Bob cancels his Spotify subscription, but keeps his Amazon subscription.... They both understand that really they both should cancel both of their subscriptions, but they're not going to hate on each other for not cancelling what they did, because they're trying to be pragmatic and understand that if we did ALL the right things in this world, we'd have almost no recognizeable life left.
So from this mentality of everyone doing what they can.... I maybe judge it based on the totality of how someone is living? Like, if someone is working for a really shitty, unethical company, doing really scary work, like developing weapons, then I'm going to expect that they're balancing that out by fully boycotting Amazon, whereas the Starbucks barista friend, I might give them a pass to still order things on there from time to time, just as a rough example. If I see someone just isn't making any sacrifices at all: Making bank at Lockheed, not donating to charity, not boycotting any companies, not supporting open source software, etc etc etc. Just NO actual activism outside of performative shit like social media posts and things that cost them no comfort, then no matter how much they dislike and disagree with their employer, I'm still going to consider them a supporter of it and frown on them accordingly.
And for my own job hunt, I guess this means that the more evil the company I work at, the more I have a responsibility to counterbalance that by giving up other comforts. And the real challenge is just to be intellectually honest with yourself and really ask if the sacrifices that you're making are worth the harm that you're doing, and if you could work somewhere else and do a lot less harm for only a little less comfort, something on that Pareto optimal frontier.