Also, in the OT times, there were populations that were entirely wicked. God ordered their destruction to keep the Jewish bloodlines separate in order that Christ could be born.
God did not destroy a society until it was thoroughly evil and beyond hope. Remember the Israelites wandered in the desert for 40 more years in part because of their sin, but also because the wickedness in the lands they were to conquer was not complete yet
God states he takes no pleasure in the destruction of the wicked, but wants all to be saved.
Hate to nitpick, but I can not help myself....the fact is that Jesus’ bloodline is not entirely Jewish. Ruth was a moabite. She married Boaz, who happened to be the son of Rahab the (former) prostitute, who had lived in Jerico and wasn’t Jewish either....We know that Boaz and Ruth were the great grandparents of King David.
God can take our mistakes and make something beautiful out of them. His line shows this. It shows his mercy and his love, and his forgiveness.