We've only been here about a million years. Modern type human about 100thousand years, sending radio waves, tv waves into space about 150years, so people who believe aliens have visited us, how would they know we are here? A radio wave travels at the speed of light, so our signals have only reached about 150light years. The nearest habitable planet is thousands of light years away. So how would they know first of all, our blue planet existed (a tiny dot even only a few 100thousand miles away) and secondly, that life even existed on our planet? And thirdly, wasting the time to cross the vast expanseses to check if there is life on our dot. I believe the universe is teaming with life, but no way has any of that life found its way to earth. Right or wrong alien hunters?