Actually it is their little infiltrated minions that are causing most of the damage and cutting lives short. Execution should only be for those that have killed or contributed to someone's death willfully.
>How about bioterrorism where individuals have died ?
Even if they don't die, their lives are either cut short or the victims suffer. They have to measured by their own stick.
You see death isn't always fair, some people have to suffer for a very long time equal to what they made others suffer. Say if someone poisoned your relative, and they had multiple tube for bodily functions for a decade as a result. A quick death penalty is not justice, they should be sentenced to the same sentence they gave the innocent.