> I don't understand why governments don't just [violate civil liberties].

Perhaps you should think a bit harder. Maybe do some reading? Maybe consider how you'd feel if your civil liberties were targeted.

> At least it wouldn't be a waste of tax payers dollars like governments are renown for doing

Sure. From the people that brought you such successes as the war on drugs, the war in Afghanistan, and the DMV. I mean, obviously a "war on people in an ill-defined category that aren't actually breaking any laws we know of" is going to be super easy to execute. No doubt it'll go super well, with no wasted resources.