If you don't know much about the novel, Pride and Prejudice is a story about a group of sisters trying to find suitable husbands.
This sounds simple enough, except the problem is that they live in England in the early 1800s, a time in which middle class women such as themselves had little legal power or freedom, and marriage is a high stakes love-and-property-rights decision for the sisters, their families, their prospective husbands, and their romantic competitors.
(Working class women not only lacked power and freedom, they also had no safety net of family wealth.)
Because this is a high stakes decision for everyone involved, it means every character has an opinion. And this is one of the hallmarks of Austen's writing: a bunch of characters judging each other. Constantly, about everything.