What Jeroboam did was sinful. And it caused Israel to sin. The people came to worship the statue at Bethel. They went all the way to Dan to worship the statue that was there.
When the Lord tore Israel from the house of David, Israel made Jeroboam son of Nebat king. Then Jeroboam led Israel away from following the Lord and caused them to commit great sin.
Yet Jehu was not careful to follow the instruction of the Lord God of Israel with all his heart. He did not turn from the sins that Jeroboam had caused Israel to commit.