Why do they have that right? Here's a car analogy - If I buy a Ford pick what right do they have to stop me doing donuts in it? Or maybe fitting a swimming pool in the back. Maybe I want to drive it around my ranch on fire. If an individual wants to use this software on their Facebook feed I really can't see what legal right FB have to prevent them. OTOH - something was probably "signed" in a EULA to prevent this.