User intervention against incivility as social enforcement of democratic norms on social media platforms is considered an act of “good citizenship” by citizens and scholars alike. However, between ideals and behavior, multiple social norms are at play in shaping individuals’ sense of personal responsibility for intervening. This study explores the role of conflicting norms in situations requiring user intervention against online incivility. By combining the perspectives of norms as expectations and norms as cultural vocabularies, we investigate users’ salient norms, and how these norms influence users’ justifications for (non-)intervention. Based on qualitative interview data from Germany (N = 20), we identified three distinct reasoning patterns employed to justify (non-)intervention: the pragmatic, the dismissive, and the aspirational. By identifying fault lines, our typology points to normative origins of ambivalence related to user intervention. The findings offer insights into strategies to motivate intervention against online incivility.