Based on the analysis of a French pre-exposure prophylaxis trial (Ipergay), and focusing on the communication strategies used to recruit volunteers, this article explores the figure who serves to justify the trial and who shapes the way in which populations concerned by this prevention tool are targeted. We show that this figure is that of the fallible man, a classic in moral philosophy: while aware of what is good or right for him, he is unable to put this knowledge into practice. The targeting of fallible men makes sense in the context of a resurgence of high-risk behaviors objectified in the late 1990s: qualifying gays who take risks as fallible individuals create a distance with respect to the "barebacker" who risks his life deliberately and has no intention of changing his behavior. Recognizing that certain gays are vulnerable to risk also provides justification for a preventive strategy that acknowledges the inadequacy of behavioral prevention, without giving up on prevention altogether. All in all, this analysis shows that the technological and epidemiological realism often highlighted in pre-exposure prophylaxis interventions is not without a moral dimension, attentive to individuals' contradictions and singularities, doubts and uncertainties, and to the risk of stigmatization inherent to the acknowledgement of risk-taking.