[alejantrot]

I get the author's fear, but how is that any worse than doing mass surveillance for a fuzzy reason like "national security concerns"?

All the totalitarian regimes cited reasons like "national security concerns" or "enemy of the people" to mass monitor their citizens. Using mass surveillance in order to catch a thief or a killer is still excessive and undermines our freedom, but at least it's a much more specific and debatable reason than chasing ghosts.