Initializing a neural net with random weights =/= making a neural net with no preconceptions on how to play. It still has those preconceptions, you just don't know what they are.
Closing your eyes so you can't see the contents of a room =/= the room is empty. Not knowing what something is, is different from it not existing
Closing your eyes so you can't see the contents of a room =/= the room is empty. Not knowing what something is, is different from it not existing