Society had never experienced anything but the shadows, so they assumed that the shadows were the whole of reality. We believe anything the government put before us and since we don’t have any knowledge we have let to believe the information that we receive is correct. This is why we are in the dark, that’s why they did not want Socrates questioning their people because they will lose control if they see things on different level.
Philosophy is supposed to be liberating by giving you knowledge to feed your soul, so you will be living a clean, free and honest life. It determines your character if you’re going to be foolish or wise. According to Plato the prisoner came to see that the shadows were only a derivative, lower level of reality compared to the realities he experienced outside the cave, he saw the light.
Socrates believed that there is no life without philosophy, yes he has the right to be pessimistic and so is anyone if they believe in something. He thinks he was put on this earth for a purpose and that’s what he was serving.