Mu Jinyu shook his head, saying, "I can tell that you are serious. You truly wish to acquire superior medical skills and to better treat patients, to prevent many from dying needlessly because of your own helplessness, to choose only to close their eyes and wait for death. You want to benefit society, and to be honest, your attitude truly moves me. But I really cannot teach you..."
Mu Jinyu was not holding a grudge against Shen Changchun's previous attitude, nor was he using it as an excuse on purpose. He simply had no way to teach Shen Changchun anything because Shen's age was indeed too great. It was essentially impossible for him to learn Jinyu's medical skills.
His medical skills were tied to a specific cultivation method he possessed. Without the True Qi cultivated from that method, it was impossible to perform such miraculous healing.
Therefore, even though he was deeply moved by Shen Changchun's attitude, he still could not teach him.