It's not about the number of lives but it is about the state of fear that grips the state afterwards. That anything can happen and government has no power to stop that.
I spent a decade in South Africa where the ANC bombed the shit out of it, and there was concern, not terror. No one I encountered was afraid, let alone terrified. Each death was a tragedy, but like the IRA terror bombings in London, people just carry on with their lives.
This is the funniest thing about the US. Some places experience actual terrorism and they don't let it control their lives. The US has one successful attack of 3k people (to be fair, that's pretty big for a terrorist attack) one time and go literally insane.
