The children of Israel didn't remember Yahweh their God, who had delivered them out of the hand of all their enemies on every side;
Most of the major judges in the Book of Judges lacked character that we would call "above reproach" (1 Timothy 3:2). God uses vessels unto dishonor as well as vessels unto honor to accomplish His work (2 Timothy 2:20-21). This in no way justifies ungodliness. It simply magnifies the sovereignty and grace of God in using rough material if He chooses to do so for His own purposes.