An idol is an object that is worshipped. Not just a representation of the agent or deity that one worships, but the object of that worship.
During the time the scriptures were written that became incorporated into the Christian bible which comment on "idol worship," there were competing gods with Yahweh/Elohim. There were also idols of worship and "graven" images -these were images that were inscribed, carved or engraved (thus the term "graven") which were considered to be actual deities, representatives of deities, or actually inhabited by the deity. These gods ranged from Ashtar, Ashera, Baal, Lotan, Ishat, El, Elsh, Shamu, Sin, and many others. Ironically, Yahweh was among these Canaanite gods and the son of El (the singular of Elohim?).
As the cult of Yahweh grew in prominence and status, it dominated other cults and began to position itself as the true cult. The birth of Islamo-Judeo-Christian monotheism is very likely the result of a fad within the Canaanites that developed into a hegemony.
The biblical phrase, "there shall be no gods before me" might actually be a literal instruction: "I'm in the statue. Put me up front and the rest behind me." Instead, modern monotheists believe this means (and they may be right) that the author of the phrase was implying that his god was the only god and other gods are false. Regardless, its an acknowledgment by the biblical author that there did exist other gods at one time and these gods had followers. People very likely followed gods for various reasons, depending on the day, season, need, etc. -adding, subtracting, and swapping as they felt appropriate.
And, yes, the Canaanites became the "Israelites." The archaeology shows this to be the case. And, yes, Yahweh is a Canaanite god.
