I argue that victims of microaggressions suffer from the problem of invisible wrongdoers, where they cannot properly respond to everyday injustice of which they become the targets, because they cannot identify these events as wrongdoings and perpetrators as culpable wrongdoers. I identify the causes of this problem as: (1) the recent transformation of explicit, 'old-fashioned' discriminations into implicit, 'modern' forms, and (2) our focus on the macroscopic perspective to examine the moral significance of oppressive practices. I propose that we tackle this problem by extending our discussion to the microscopic level. In this paper, I offer a positive account of why microaggressions are moral offenses that merit blaming and critical responses from victims, and respond to three excuses given by perpetrators of microaggressions, namely, (1) that the act itself was trivial, (2) that the agents were well-intentioned, and (3) that they were non-culpably ignorant at the time of offense.