It's not nice to induce terror in little children, or anyone else, for that matter.
It's not nice to manipulate people's emotions, though that's what we pay Hollywood to do all the time, in movie theaters and the comfort of our own homes. We pay our dollars and decide when we've had enough. Whatever we might have thought, virtual terrorizing does not prepare us for the real thing.
Terror, being an emotion, is not something we can easily turn off. Turning it on is a snap. And once the program is in place, even fleeting images without any sound can set it off. War, being a fearful thing itself, can't be waged against terror. So, from the start, the war on terror was a hopeless enterprise. Partnering it with law enforcement was, at least, honest. The object was to use terror to make people behave themselves. Or, even better, do nothing except what they're told. People made timid by terror are, indeed, pacified.
Terrorizing a whole nation from the Atlantic to the Pacific was a singular accomplishment. But, if only because all men are mortal, terror regimes are relatively short-lived. Terrorism is the wrong tool for long term rule.