But by definition the founders of the USA were terrorists. And they knew it too, viz. Benjamin Franklin's famous line 'Gentlemen, we must all hang together or we shall most assuredly hang separately.'

Preemptively invalidating all non-state actors is just a way for people with power to avoid challenges to it. Every single oppressive regime describes rebels as terrorists and employs circular arguments to assert its own legitimacy. Using this to dismiss military attacks on military targets is, frankly, bullshit.