Final answer:
Conflicts and discrimination by white slaveholders in Texas made Indigenous tribes and Mexican settlers hostile to the Confederate cause, as the American settlers clashed with these groups over religion, slavery, and land ownership.
Step-by-step explanation:
Decades of conflicts and discrimination from white slaveholders in Texas made Indigenous tribes and Mexican settlers hostile to the Confederate cause. These groups faced persistent racism and entitlement from white settlers, and government-sanctioned land acquisitions left them at a profound disadvantage. The dislike of most for Roman Catholicism (the prevailing religion of Mexico and often held by Mexican settlers) and a belief in American racial superiority further aggravated relations between the white American settlers and local Mexican populations. Moreover, the American settlers in the Mexican province of Texas were distinct from tejanos because many were slave owners and remained religiously distinct from the Roman Catholic tejanos. The confiscation and threats towards Mexican landowners, along with disagreements over slavery, exacerbated tensions and ultimately led to a revolt by the American settlers.