US Defense contractors recruiting offensive attackers by the hundreds

That would be a ridiculous point, unworthy of debate.

Nation states around the world owe their first allegiance to their own interests, and then to the interests of their long-term economic and geopolitical prospects, and then maybe to their people. Any allegiance owed to principled conduct in "cyberspace" is way, way down the list. Any rival of the United States has an advantage that can be prosecuted using offensive security research is assuredly already doing so.

I also take issue with your last sentence, with the idea that the US was the first state to directly engage foreign targets. Obviously, the words "of major military significance" gives your argument a lot of room to maneuver, but the overall effect of the argument as it stands is that the US is the only state pursuing any kind of meaningful offensive security effort. That's almost definitely not the case.

I'm also unclear as to why I should be particularly disturbed by the weaponization of IT. Let's stipulate for a moment that Stuxnet was a weapon intended to sabotage a covert Iranian nuclear weapons program. OK. And? What moral authority does Stuxnet lack that a laser-guided bomb dropped from a jet owns? Did Stuxnet kill anyone? To the extent the US military can accomplish objectives using technological countermeasures rather than explosive munitions, I call that progress.