"用道德解释" can be translated into English as "explain in terms of morality" or "interpret from a moral perspective".
"Explain in terms of morality" emphasizes using moral principles or values to clarify or justify something.
"Interpret from a moral perspective" focuses on analyzing or understanding something based on moral considerations or viewpoints.
Both translations are contextually appropriate, and the choice between them may depend on the specific nuance you wish to convey.