False. Luther left the church because he was excommunicated. He never wanted to leave the church, but to reform it from within. He was kicked out, he never willingly left.
He never really tried to Get"back in." IAC, Excommunication does not mean that one is kicked out of the church, only that one is under sanction. Usually that can be lifted by the accused tries. But he refused to recant.
Very well, but that is essentially a technicality. The point being was that Luther's beef with Catholicism had as much to do with doctrine - if not more - than corruption.