Since the end of the 19th century, three combat sports - Boxing, Muay Thaï and Mixed Martial Arts -, unlike from their regulatory framework and their technical specificities, became, successively, the target of analogous moral criticisms, even "moral crusades", proceeding as well from politicians, sport managers that journalists. In a recurrent way, these activities have been accused of being extremely brutal and immoral, of transgressing the sport values, even of breaching the human dignity, before of being, gradually, socially accepted and considered as an educational means. The aim of the present work was to specify the historic circumstances of these moral campaigns, articulating permanence in their principle and variability in their target. Trying to conceptualize their social driving forces, we discussed the hypothesis that the successive focalizations of the moral sentences against the three disciplines could result from the conjunction of a social stigmatization of their marginalized players and the necessity to define, in a context of values crisis, a consensual standard of the moral monstrosity.