I did indeed look up the link you provided. All the UFO cases of which I am aware have plausible explanations not involving aliens, extraterrestrials, or other unknown human races. So although I think it very likely that life exists on other planets, given the realities concerning the vastness of space, I seriously doubt that any of them have been here. The link mentions an ancient earth on which many past civilizations have come and gone, some destroyed by catastrophic events such as nuclear war. No evidence. We do have evidence that shows the earth to be around 4-1/2 billion years old and can see the major outlines in the history of life in the fossils.

Next, although evolution on this planet may give the appearance of progressive design, this is not the case. What we do is a gradual accumulation of many small changes that gave a slight survival advantage long enough to reproduce. Along the way, there have been many dead ends, possibly Neanderthals as an example. This is not what one would expect if there was a progressive design by an intelligent director. You can see some discussion of this here and some on hominid evolution here. The latter link shows that homo erectus seems to have survived long enough to have descendants not in our ancestral line.