No one on here knows for a fact that they closed the doors, to that point you are correct, but we do know a lot of disheartening facts through which we can draw a conclusion.
For instance, if you have a child and then start failing in school, they have trouble concentrating, their eyes are red, they seem spaced out etc..with those FACTS you can draw a conclusion that they might be on drugs. It's speculation until they admit it or take a drug test, but its a hypothesis based on facts.
What facts are you basing your hypothesis on?