oh, there's lots of evidence...videos from different sources of the same event, records in sumerian texts, eyewitness accounts, removal of foreign matter, which cannot be identified, from those who claim to be abducted, and so on, and on, for over 5,000 years.
When you have huge ego assets tied up in belief systems, any threat which exists to that belief system, no matter how valid, will be discounted.
I know: ALL those people are making it up, all the videos are fake, and everyone who suffers ridicule by reporting these things do it for the glorious reward of insults and denigration by others.