This may have been due to Munemori's mental weakness; however, it is also thought that another reason could be the difficult position in which he was placed in the conflict between Kiyomori and Goshirakawa.
宗盛の精神的弱さとも言えるが、清盛と後白河の対立の中で苦境に陥ったことも理由の一つと推測される。