As debate persists over regulating electronic nicotine delivery systems (ENDS), those favouring liberal ENDS policies have advanced rights-based arguments privileging harm reduction to people who smoke over harm prevention to children and never-smokers. Recent ethical arguments advocate regulating ENDS to prioritise their harm reduction potential for people who currently smoke over any future harm to young never-smokers. In this article, we critically assess these arguments, in particular, the assumption that ethical arguments for prioritising the interests of young people do not apply to ENDS. We argue that, when the appropriate comparators are used, it is not clear the weight of ethical argument tips in favour of those who currently smoke and against young never-smokers. We also assert that arguments from a resource prioritisation context are not appropriate for analysing ENDS regulation, because ENDS are not a scarce resource. Further, we reject utilitarian arguments regarding maximising net population health benefits, as these do not adequately consider vulnerable groups’ rights, or address the population distribution of benefits and harms. Lastly, we argue that one-directional considerations of harm reduction do not recognise that ENDS potentially increase harm to those who do not smoke and who would not otherwise have initiated nicotine use.