Sorry - but I don't see this as pilot error at all. For a system as sophisticated and (ostensibly) mature as Predator to have such a human factors issue points the arrow of probable cause back to the designers.
No certificated manned aircraft would have such an ambiguous control system. There are good reasons cockpits of manned aircraft are standardized, and an unmanned aircraft with a 66' wing is no less a hazard to other aircraft (or to persons on the ground) than a manned one the same size.
And so yes, the pilot was in error, but he had a LOT of help.
