To me, there is no question that they have been visiting the Earth for a long time. For example, there are ancient monuments that it would be difficult or impossible for us to do today. They couldn't have been done without the help of extraterrestrials. But the civilizations who built those impressive feats of engineering all share one thing in common. They all disappeared. So whatever the ET's may have been doing to help those peoples in the past, it apparently didn't do them any good.
Today, I have been hearing stories from high ranking government officials that some governments are in contact with ET's. But it is kept strictly secret. From what they say, it is the ET's themselves who don't want their existence to be revealed to the human population at large. They apparently say that humanity isn't ready for such knowledge. According to one top scientist who fairly recently passed away, he said that we were getting technological assistance from ET's. He even held up a picture of one. The video he made was sort of a death bed confession. Because he knew that he wasn't going to be around much longer. And he felt the truth needed to be known.
No doubt to keep receiving such technical assistance, we must agree to their wishes to not let their existence to be known openly to humanity. The thing is, as I said, peoples in the past had received help from ET's. And it did their civilizations no good. Because they disappeared. Even though we today are also receiving assistance from ET's, ultimately, I don't think it is going to do us any more good than it had to disappeared civilizations in the past. To me, that doesn't seem very friendly.