It is true that work confers dignity and self-worth on a person. Unfortunately many people know nothing but welfare so they will never know what it is like to be a contributing member of society. People on welfare tend to be unhappy and miserable people.
Merely being dependent on welfare does not change the inherent human desire to be a part of the society and contribute to it.
This is what makes these folks unhappy. They recognize that they're failing to meet one of their basic human roles and functions in life.
This woman's suggestion that it's "stupid" to work is a reflection of her inability to be who she is supposed to be. It's unacceptable to her and she reacts cynically and lashes out against those who are succeeding.
She recognizes what an abject failure she is but can't come to admit it.