OK, this is a tough one.
At the very end, we find out that this is not a statement of something that happened, but a parable about this evil generation.
The Pharisees, along with the other people when Jesus was among them, had a great opportunity. Can you even imagine what it must have been like to meet Jesus in person and hear him teach? Watch him heal? Maybe even be healed?
But if the people just enjoy his ministry and essentially use him as a healer, but don’t turn to God, it will be worse in the end than it was before Jesus came.