I genuinely believe (perhaps naively) that there are good people, and we do crafty things to pursue our interests, but we punch the clock out at some point and respect that the battle of our conflicting interests must cease so we can return to being people. This is predicated on the idea that we are just humans recognizing we are dealing with other humans, and we will find an equillibrium of interests at some point. Where that breaks down is when we lose sight of that and just start to exterminate each other for its own sake by all deceptive and mendacious means necessary. For that you have to give up your own humanity first. Maybe that view is as quaint as the famously naive "gentlemen do not read each others' mail," statement, but without some guiding humanity, we might as well just use biological warfare because the only thing stopping using that is polite convention. Some rulers have been content to rule over slaves and disposable subjugated automatons reduced to living like animals, but their ambition is meaningless and unsatisfying because without some assent, they do not rule over people. When you have subjugated a people, the only solution is to find more people to subjugate. It's on everyone else to engage in total war to prevent that from happening, imo.
That's a big philosophical hope statement, but in terms of the ethics of building these tools, the truly evil empires have their own infrastructure, and don't need tools like those made by the NSO's of the world. Globally, and species wise, NSO's clients aren't the problem.