Why were heretics treted so badly?

Heretics were treated harshly primarily because their beliefs were seen as a direct challenge to the prevailing religious and social order, particularly in medieval Europe. Authorities believed that heresy could undermine the unity of the Church and society, leading to moral decay and social unrest. As a result, harsh punishments, including torture and execution, were often justified as necessary to protect the faith and maintain public order. This persecution was fueled by a combination of religious fervor, political power struggles, and the desire to eliminate dissenting views.