What prompted the Greeks to worship the fallen angels as their gods?

Maybe this will help

Angels are primarily a concept of Judaism, though the Greek word aggelos ("messenger") does have some use in Greek religion relating to divine messengers.[7] The followers of the pagan monotheistic religion, Hypsistarianism worshipped the "Most High", Hypsistos, Jewish God and acknowledged the Gods of traditional Greek religion as angels.[8] But the reference to angels is still from Judaism, not paganism, and some modern scholars identify the Hypsistarian groups, with Gentile God fearers, that is to say uncircumcised semi-proselytes to, and sympathizers with, Hellenistic Judaism.

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Don't know, maybe the same thing that prompts Christians, Jews and Muslims to worship the false "God" Yahweh...

Jesus taught--satan is the ruler of this world( system of things) Have you read the bible? all throughout Mankind' history = 99% mislead--99% false religions. I believe its the same today. This coming for the earth--its sad--revelation 16--- satan misleads every kingdom( govt, armies, supporters), on earth to stand in opposition to God at Har-mageddon--with 3 inspired expressions( misleading). For patriotism how many will fall?

The Greeks were writing about their gods before the Hebrew gods were invented.

They had power and people were lead by fear back in those days

They said, "We aren't chosen people, we might as well worship zeus"

No clue

Superstition my friend...