Why was Israel so prone to idolatry after leaving Egypt?
Israel's prolonged exposure to Egypt's pervasive idolatry and paganism left them saturated with false worship. When Moses remained on the mountain forty days, they grew impatient and demanded gods, revealing how deeply Egyptian idolatry had shaped them. Thus their idolatry arose from Egypt's influence and their impatience.
Les explains that coming out of Egypt, Israel was just saturated with the idolatry and paganism of the Egyptians. While Moses was up in the mountain the first time receiving God's instructions, he was gone forty days. During that absence, Israel got impatient and asked for gods, saying, "Make us gods." Les notes that it is hard for us to comprehend this, and that we are so easily brought to the place where we condemn the Jews.