People who do not wantrefuse to hear do not need anyonelisten cannot be forced to make them deafhear. People who do not wantrefuse to see do not need anyonecannot be forced to make them blindlook. 'Deaf and blind' is a metaphor to describe the symptoms of these people. The Lord sent Isaiah to tell the people their symptoms, but comfort him in advance that the people would not listen to him, otherwise they would be healed.
It is worth noting that in open fields, there were two kinds of people who came to Jesus. One kind was looking for food, and another kind for His words. The people who were looking for food did not prioritize understanding the kingdom of God, and were deaf and blind in this sense. The people who were looking to know Jesus had no issue understanding His parables. When Jesus was with His disciples in private, He did not use parables.
In John 12:37-43 and Acts 28:23-28, John and Paul gave the same interpretation. It was the people who resisted believing in Jesus caused them to be deaf and blind. However, this statement is always quote after: "Otherwise they might see with their eyes, hear with their ears, understand with their hearts and turn, and I would heal them". This statement is a promise of God, who will forgive the sin of those who repent.