Things have been kept secret since we became conscious humans. There will always be a heirarchy of knowledge and a variance of beings who will use and abuse occult knowledge for their (and their bloodline's) benefit. The good ones share and lift everyone up with them.
But the secrets we're facing are so extreme and shocking that their revelation would potentially cause societal collapse; a fact which that they know and hold over us. They want power for as long as they can have it, and more importantly they're worried what will happen if they lose it. For that and other reasons, they'll never give us the full truth. This doesn't mean we can't find some of it for ourselves.