Re: end user
Well, this needs some analysis. We'll start with the easy part:
"Your original post makes no mention of NSO, only knives, nukes, and exploits/malware."
Well spotted. I was referring to spyware. The article referred to spyware too, wouldn't you know. And the group making it was NSO. The original comment in this thread was making an analogy about holding NSO responsible. My reply was making a counter-analogy to that. I figured that link was obvious, but evidently not. For clarity, the rest of this comment will be discussing NSO and the legality of its spyware.
Now, let's talk about tanks. Lots of considerations. The first one is easy: making a tank causes no damage to anybody. Operating it might, but creating one is not much different from manufacturing some other type of vehicle. Malware creation often involves finding vulnerabilities in a system through penetration, which happens to be illegal. So manufacturing a tank has no intrinsic criminal elements but manufacturing malware does. For the analogy, manufacturing nukes or nerve gases may not in themselves be dangerous activities, but they would be contrary to various laws in most nations, including, for the nerve gases, the Geneva protocols.
Now, when tanks are made for militaries, they are made at the specific request of the military, under a contract. Sometimes it's a contract from an international military and the laws permit this. This means the production of the tank can be attached for determining responsibility to the manufacturer and the military that is on the other side of the contract. If the manufacturer does something illegal that the military has the right to allow them to do, the military can essentially make that legal. NSO did not create their products under contract, and they can claim no such immunity.
Certain countries may modify the laws allowing them to create and use malware. That does not make it legal in the way you're arguing. If Israel wrote a law allowing their government to create malware, which they have done, it doesn't give NSO the permission to do so unilaterally--only places controlled by or under contract to certain parts of the Israeli government have the special permission. If Israel's government did allow NSO to make the malware under that special legislation, which they don't appear to have done, it wouldn't make it legal for them to sell it to other governments or individuals. And if Israel's laws allowed NSO to do anything they wanted including break into systems to create malware for any purpose, which is not at all the case, it would not stop those actions from being illegal in other countries such as the U.S., which they are. If I start my own country, and my laws say that I can hack into your bank account and steal all the contents, I can still be arrested should I ever leave my country, because bank theft isn't legal where you are.