The same goes in reverse. If the US faked a moon landing why didn't the soviets scream about it? why aren't the russians and chinese still screaming about it? They have the capabilities to prove the falsehood, why haven't they?
The aren't screaming about it, because it was a conspiracy between top US leaders, to soviet leader and top Chinese leader. Your reasoning just proves the conspiracy.
(Just joking, of course. But you know that's what the conspiracy theorists will say).
Fundamentalism - the anti-American, anti-Christian branch of American Christianity