@regineheidorn The crucial component is not mental illness at large, either cognitive decline or break with reality in particular.
Here's a relevant study:
Abstract
Despite their important implications for interpersonal behaviors and relations, cognitive abilities have been largely ignored as explanations of prejudice. We proposed and tested mediation models in which lower cognitive ability predicts greater prejudice, an effect mediated through the endorsement of right-wing ideologies (social conservatism, right-wing authoritarianism) and low levels of contact with out-groups. In an analysis of two large-scale, nationally representative United Kingdom data sets (N = 15,874), we found that lower general intelligence (g) in childhood predicts greater racism in adulthood, and this effect was largely mediated via conservative ideology. A secondary analysis of a U.S. data set confirmed a predictive effect of poor abstract-reasoning skills on antihomosexual prejudice, a relation partially mediated by both authoritarianism and low levels of intergroup contact. All analyses controlled for education and socioeconomic status. Our results suggest that cognitive abilities play a critical, albeit underappreciated, role in prejudice. Consequently, we recommend a heightened focus on cognitive ability in research on prejudice and a better integration of cognitive ability into prejudice models.
Source: https://pubmed.ncbi.nlm.nih.gov/22222219/
In the modern day, the Fox News effect, of pulling the elderly into extreme politics as they age, is easy to see. Fox News as such might not have existed in the early 20th century, but the Hearst newspaper empire definitely did.
@mekkaokereke