Hammers make a great murder weapon. Guess what, they also build a nice house.
You don't make my hammers grow in size(value) because you keep using yours. Also there could be unlimited hammers in the world not 21m
Since I'm having trouble understanding what you are trying to convey, I'm going to go out on a limb and guess.
Are you suggesting that if a terror cell uses Bitcoin for their nefarious purposes, my bitcoins will be worth more, therefor I am benefiting from the actions of the terrorists?
http://en.wikipedia.org/wiki/Parable_of_the_broken_windowI'm trying to see his meaning too, but there's a situation that closely relates to what he means.
HSBC is used by Columbian drug dealers to launder money. Are you going to stop using HSBC?