Scientific disputes about public health issues can become emotional battlefields marked by strong emotions like anger, contempt, and disgust. Contemporary work in moral psychology demonstrates that each of these emotions is a reaction to a specific type of moral violation. Applying this work to harm reduction debates, specifically the use of smokeless tobacco to reduce harm from tobacco use, we attempt to explain why some public health disputes have been so heated. Public health ethics tend to emphasize social justice concerns to the exclusion of other moral perspectives that value scientific authority, professional loyalty, and bodily purity. An awareness of their different emotional reactions and underlying moral motivations might help public health professionals better understand each others' viewpoints, ultimately leading to more productive dialogue.