Why is caring for the weak for society and each person important?

I believe that caring for the weak is the most important component of any social order. In ancient times, it was customary to get rid of weak people. They were a burden for the tribe, pulled everyone back, did not bring prey. But over time, the attitude towards weak people has changed. Not only physical strength is important, but also mental development. People who are not so physically developed can have phenomenal knowledge. Very often such people become famous scientists who make sensational discoveries.