but every man did that which was right in his own eyes.”
The generation that followed Joshua did not set out to do evil. They did not think they were doing wrong. Rather, “they did what was right in their own eyes.”
That's the problem with sin; the sinner feels justified. Like the people in the book of Judges, they compromise with the world around them. They create their own religion keeping what they like about Christianity, dumping what they don't, and adding elements that feel right.
Part of the problem is second-generation syndrome. “After that whole generation had been gathered to their ancestors, another generation grew up who knew neither the Lord nor what he had done for Israel.” Judges 2:10
Previous generations did the hard work. Moses' generation endured the slavery in Egypt. They saw the Red Sea part and Pharaoh's army drown. They enjoyed God's provision in the wilderness.
Joshua's generation conquered the land. They saw the walls of Jericho collapse. They saw their enemies fall before them. They took the land, city by city, mountain by mountain.
On the other hand, the Judges generation entered into rest and comfort provided by their ancestors. Joshua told them, “I gave you a land on which you did not toil and cities you did not build; and you live in them and eat from vineyards and olive groves that you did not plant.” Joshua 24:13
He admonished them further, “Now fear the Lord and serve him with all faithfulness. Throw away the gods your ancestors worshiped beyond the Euphrates River and in Egypt, and serve the Lord. 15 But if serving the Lord seems undesirable to you, then choose for yourselves this day whom you will serve, whether the gods your ancestors served beyond the Euphrates, or the gods of the Amorites, in whose land you are living. But as for me and my household, we will serve the Lord.” Joshua 24:14
The people said Amen but failed to honor a God they did not know. They married outside the faith and failed to take down the pagan altars. They kept the holy days and cultural artifacts of the faith but not the faith itself.
You cannot inherit faith from your parents. Each of us is called to account. Jesus said, “I am the way the truth and the life. No one comes to the father except by me.” John 14:6
It is easy for those who have grown around the faith to fake it. They talk about being blessed and pray for things they want. They may, even, attend worship with some regularity but their walk is inconsistent. Like the Israelites in Judges they sin, feel sorry for awhile, then sin again.
There is good news: “To all who did receive [Jesus], to those who believed in his name, he gave the right to become children of God.” John 1:12