"As the elders said, if one finger brought oil it soiled the other" How does this explain the harsh punishment given to Okonkwo

THe Elders feel that Okonkwo's actions bring disrepute to the whole village. Okonkwo's gun went of as a salute to Ezeudu but killed a boy in the funeral crowd. This would certainly anger the earth Goddess. If punishment was not exacted from the guilty, the whole village would suffer.