I am of the same point of view as you are that the killers are responsible for the deaths not the movie, that is why I used the words "due to". But you can not deny the fact that everybody in this world is not educated to the extent that they can differentiate in between right and wrong. They only try to balance the equation with cause and effect. Fire needs a source (like the short movie provided) to become inferno. To avoid that inferno, somethings including limits to free speech must be implemented.