Obviously we know that the crucifixion was the watershed event in human history.
What the pope was saying is that to those who were around Jesus, viewed from their human perspective, it appeared a failure. The lesson for us, as believers in God’s greater purposes, is not to view circumstances as failures. We have a complete revelation and know that God wins.
The desire to declare Francis the false prophet is so strong on this forum.
The problem with what the pope said is that he left it at that. Had he added that from God’s perspective it was the ultimate victory, you would have a point.