The Ewoks were previously visited by a gold protocol droid. At least 1000 years previous. It was a beneficial encounter. Perhaps this is where they acquired knowledge to build gliders, but this was not the main benefit associated with the event. Probably the protocol droid had aided in repelling an invader in some minor way. A droid does not eat, breath, deficate or use genitals. God-like properties yet no god-like powers except the gift of tongues. Merely associating the coming of the 'gold deity' with the victory is sufficient and likley. Later, there was a legitimate prophecy given by a force sensitive ewok that another gold deity would come and help repel invaders (the prophecy, or the prophet, left out the presence of human companions). Ewoks knew but did not nessissarily count on the prophecy. They would not and did not expect the gold deity to have companions or powers other than tongues. When the prophecy proved true (gold deity with tongues when an invader is near), there where no sceptics. When the gold deity claimed powers, this was inconsistant with their knowledge of the gold deity, thus, they were skeptical and 'fear-of-god' shocked when the gold deity demonstraited flight without wings or a machine. So what if flight was 'otherwise normal' to ewoks; "What other powers has he be hiding?" was certainly in their minds. "Can he shoot beams, call fire from the sky, command earthquakes?" Ewoks knew stormtroopers could do all that, but they didn't expect it from the gold deity.