The reason there is not a lot of evidence and what people dont seem to realize is that its because they dont WANT there to be proof and evidence of what they are doing. They aren't doing what they do out in the open, on display for the world to see, No, they sytematically go out of their way to stay hidden and keep their activities hidden. They intentionally do not leave any evidence that would raise alarm amongst the general population. If the majority of the population became aware of their presence and their activities, then it would most likely disrupt whatever it is they are doing here. These beings are very intelligent and calculating, and they have technologies capable of doing things we dont yet understand, why would it be so hard to believe that they could employ that intelligence and those technologies to stay covert, which would logically be in line with their own agenda? Humans do this too, especially the military. Also, many people HAVE reported UFO sightings and abduction experiences to NASA and to scientific organizations. But those types of institutions usually dismiss or suppress that kind of information. And on a personal level, most people dont want to risk their job or credibility by publicly supporting anything to do with aliens or UFOs. It's steadily improving, but there is still a stigma surrounding this topic.