The Pope is in a difficult position. If he were to state that the principles taught by St John Paul II were no longer part of the Church’s teaching, he would cause a theological earthquake. Never in modern times has a pope publicly disavowed his predecessor. To do so would provoke open revolt among the many who cling tenaciously to the doctrine of previous popes – not merely the last two, but the entire Catholic tradition as it has evolved over the centuries. It might even provoke a formal schism.full article at UK Catholic Herald
What’s more, it would relativise Pope Francis’s own teaching authority – after all, if his predecessors got it wrong, why should anyone think his own statements had any lasting value beyond his lifetime?