Chafetz Chaim Yeshiva is into Mussar, both the study and practice. That’s why they are mentchlich. Their Mussar aims to be positive and uplifting (as opposed to being heavy-handed).
To find out more about their Mussar/outlook do a search on “Rabbi Akiva Grunblatt” their Mashgiach Ruchani. You can listen to his Mussar Shmuzim.