You can "justify" so much with that sentence, that it becomes meaningless.
Also, it won't hide the fact that this surveillance infrastructure can cause much much more harm then it prevents. We've seen what it might do in repressive states and we see today that even those states which represented the idea of individual freedom on this planet, you are only one election away from madness.
"can cause much much more harm."
Cars kill way more people than guns per year. Where do you draw the line on something as subjective as this? It has the capability to cause harm but has it to the degree you're talking about? Its debatable.
Also, taking a serial killer who murdered 8 women and dismembered several of them off the streets to me outweighs quite a bit of harm. But that's just me.
Isn't that true of almost every restraint on the state's power?
A lot of less intelligent people get very emotional about the state quartering soldiers in homes against the wishes of the homeowner. But if you've got nothing to hide, you've got nothing to fear. We may not know who the Zodiac Killer is but I can tell you one thing for sure - he didn't have four to ten infantrymen in his house, keeping track of his comings and goings. Given the obvious security benefits of having soldiers in your home, no rational person would object - unless they've got a meth lab in their basement. /s