No vendor has the ability to stop their content from being used for illegal purposes.  Its impossible to prevent.  The end user is responsible for their own actions and they are responsible for the concequences of those actions.  Cars do not carry labels stating "do not kill people with this vehicle" nor is it required of any manufacturer in any country.  Why?  Because people are expected to use common sense when operating a motor vehicle.  If the end user cannot excercise common sense that is their problem and theirs alone.  NO ONE who produces content, paid for or free, should be held responsible for the illegal actions of their customers.