Found someone you have, hmm?
Actually, the galaxy is overflowing with intelligent life, but only two species have any clue we exist, and of them, only the "greys" actually have up-to-date info (the last time the bittarii were here was several thousand years ago).
The greys are actually slaves to the bittarii. They're keeping us secret because they want to use us as weapons.
And no, they're not evil, they're just really, really scared of us. They are the only creatures in the universe who're aware of just what we're capable of; they have good reason to be petrified.