Final answer:
Resentment towards the papal curia arose due to the Church's entanglement in political affairs following the investiture controversy, the evident corruption and nepotism within its ranks, and its attempts to claim both spiritual and temporal power.
Step-by-step explanation:
Petitioners and litigants resented the papal curia in the late 11th and early 12th centuries for several reasons. Following the investiture controversy when Pope Gregory VII banned simony, the spiritual authority and legitimacy of rulers such as Holy Roman Emperor Henry IV were challenged, leading to discontent among secular leaders who lost control over religious appointments.
Additionally, the corruption within the Church, including simony and nepotism, along with the papal claim over temporal power, alienated many. As the consolidation of the Church's power grew, its involvement in political matters and worldly issues detracted from its spiritual responsibilities, creating a sense of resentment among those who saw the Church as distracted from its pious duties.
During the Great Western Schism, the papacy's reputation suffered significantly due to disputes over papal legitimacy, resulting in multiple simultaneous popes and weakened religious authority. This period further fueled resentment as the papacy appeared deeply entrenched in factional conflicts rather than serving its religious community. The Church’s focus on maintaining power, whether through the Inquisition or by resisting reform movements, also contributed to the resentment against the papal curia by those who saw these measures as an abuse of authority.