The whole point of weapons is to help murder civilians. If weapons were only useful when pointed at military personnel, nobody would fear an invading army or even bother putting up resistance at all: what is that army going to do, exactly? Just get into street fights mano-mano without weapons?

Weapons are created so they can be pointed at living things, regardless of who they work for. I'm not defending NSO but let's not pretend selling exploits is any different to e.g. a Tazer or rifle manufacturer.