Risks of day-to-day activities are known, their distribution effectively fixed and the magnitude of the risk also understood. The probability of ladder falls tripling year-to-year is of order 10^-14. I understand that driving my car could potential result in my death. There is some variability in the risk depending on how careful I am, time of day, whether I am sober etc, and of course risk out of my hands from other road users. I can have a good understanding of the risk and factor that in whether to carry out a daily activity.

War and Terrorism is completely different. When they occur is unknown, whether the event is small or cataclysmic unknown, the secondary effects they have in a wide complex system unknown.

You can take the original argument even further to understand why it is silly. Atomic bombs have only been used against people twice, therefore the chance of you dying in a car crash are multi-million times higher than dying from an atomic bomb. Should there not be an intense focus on de-proliferation, de-escalation of conflicts because of this? The consequences of an nuclear attack are so great, we spend huge amount of resources to reduce the likelihood.

Terrorism is similar. It is not only the poor victims of the attack who suffer. Our societies function on a fairly fine balance, much of which is predicated on the ability of our governance to keep us safe. Rapidly increasing frequency of attacks and their effectiveness drive us closer to instability and can severely damage our economies.

You dying in a car crash is going to hurt your friends and loved ones. You being blown up along with 50 passengers on the underground, the fifth explosion that week can have dramatic and scary results for us all.