The popularity of the flagellant movement in the German speaking lands during the Black Death is due to a number of factors. Flagellation may seem like a nonsensical reaction to despair from a modern perspective, but for medieval people, the itinerant processional penitent pilgrims represented more than a bloody, painful spectacle. Rather, it was a rational and emotion reaction to their troubles. The success of the flagellants lays, not in the grotesquerie of their performances, but instead in their ability to provide people with familiar, engaging ways to perform and observe penance while also departing from ecclesiastical norms that had failed to protect Christendom.
Gobel, Eric A.
"Liturgical Processions in the Black Death,"
The Hilltop Review: Vol. 9:
2, Article 5.
Available at: https://scholarworks.wmich.edu/hilltopreview/vol9/iss2/5