This sentence comes from "Li Sao", "Although I am still alive, I am still dead". The general idea is that although you are on a certain day in your life, you actually seem to have lived for a long time. For a poet who cares about his country and people, seeing the gradual decline of this ancient empire from the day he was born, he will naturally feel strongly that he lives in a country that seems to have lived for a long time without the decline of life.
For Lu Xun, he has been awakening the numb souls of Chinese people through his own articles. In Lu Xun's eyes, the country is his life, and he devoted almost all his energy to saving the country. However, he found that his strength was limited, and no matter how hard he tried, he could never change the fate of the country's decline. So he often feels that although he is still alive, his life has lost its meaning.
Therefore, the phrase "although the date of birth, the year of death" expressed Lu Xun's heavy mood. He deeply felt the personal weakness and the decline of the country, and his heart was full of pain and despair. This kind of mood runs through Lu Xun's life and is also reflected in his articles.