Political and religious movements often bind around shared mobilizing narratives.In their most devoted activists, this triggers moral motivations to affirm and protect the narrative from being argumentatively challenged (i.e., orthodox mindsets), with free expression and nuance as the primary casualties. The ideological narratives are often threat-based, denouncing an evil or villains encroaching on a sacred value, such as national grandeur, the faith, or class, racial, or gender equality. Their protection triggers repressive reactions ranging from expressions of outrage or public shaming on social media to the “deplatforming” of controversial speakers to censorship and imprisonment of dissidents. Orthodox mindsets are puzzling because of the often disproportionate righteousness with which they try to protect cherished narratives. We suspect that orthodox mindsets may derive from three main evolved cognitive foundations. First, over-sensitive dispositions to detect threat, from human outgroups in particular. Second, motivations to mobilize ingroup members for cooperative benefits and against rival groups by emphasizing goals relevant to everyone. Third, signaling personal devotion to causes one’s allies value to accrue prestige within the ingroup. In line with arguments about self-deception, strategies of ingroup mobilization and signaling may be most likely to meet their evolved functions when displayed by activists sincerely committed to the ideological movement’s tenets.