Why is it hard to understand that Israel turned to pagan idols?
It is hard to comprehend because Israel had Jehovah's manifest, miracle-working power in their midst, yet still turned to pagan idols. The context explains their failure to destroy the Canaanites left those peoples influencing them, and that influence took them directly into idolatry during the period of the Judges.
Les explains that Israel failed to destroy the Canaanite people as God had instructed. They became soft-hearted and thought they could use these people for servants, so they left off destroying them. Just as God promised, the Canaanite people had an effect on Israel and took them right into idolatry. Les notes this is hard to comprehend because Israel had all the manifestation and miracle-working power of their Jehovah God in their midst, yet they would turn to pagan idols. During the 300 to 400 years of the book of Judges, Israel's history was a roller coaster, reaching spiritual heights under a good judge and a God-centered government.