Final answer:
Resentment toward Mexican landowners arose due to U.S. land distribution policies following the Treaty of Guadalupe Hidalgo, which led to the dispossession and economic marginalization of Mexicans and Mexican-Americans.
Step-by-step explanation:
Resentment toward Mexican landowners primarily stemmed from land distribution policies, which were influenced by economic disparities and racial antagonism. Following the Treaty of Guadalupe Hidalgo, U.S. policies led to the systematic dispossession of Mexican landowners. Mexicans and Mexican-Americans lost valuable lands that were claimed to be based on 'imperfect' land deeds. This process transformed many former landowners into laborers on the very lands they once owned, exacerbating economic and social inequalities. Additionally, Mexican laborers faced exploitation and were paid significantly less than their White counterparts. Discriminatory laws like California's Greaser Act were also enacted to target and politically disempower Mexican-Americans.