Yes David Icke has talked much on this subject and I think he has made a valid point, it is also possible what he postulates as the real story and that is scary
There is a big flaw in David Icke theory. He do not believe in ancient international air travel. The world was exchanging culture in the ancient time. Similar bed time stories between continent is natural.
In my culture, other being do not have reason to kill human. Human is naturally attracted to the power the other being can provide. Not neccessarily evil skill. It ranged from healing to killing. Fortune, fame, physical power, or any other greed.
There is power struggle in the other being world too. It shows clearly on how channeler bad mouthing the source of other channeler. They live longer, they hold more knowledge, they can alter human body, it is something natural. But if you want their power, you must prepare to loose something.