Cobweb:
You may have a point, which I have never thought about it. But I don't think that I am defending them when I say you cannot expect an organization to prevent the harm of a third person by one of it's members. That would be similar to saying if you are apart of an IEEE which is an association of professional engineers, and one of those members commit a crime which has nothing to do with their membership in that organization, would that organization be responsible for that person's actions. I don't think so, that person acted upon their own. Should they have known that he was going to commit that crime, there is no way for them to have known that. Now if that organization knows what that person did and puts him in a position that might help him re-offend in committing that crime, then yes that organization had a duty to protect that subsequent crime, but they could not stop the initial crime.