The exact same mechanism is used to keep poor white Americans voting Republican: even if they're poor, they see themselves as the white ruling class over black and Hispanic people, despite the fact that they themselves are kept poor by the real ruling class.
You're missing the symmetry. The two party system is a false dichotomy. The enemy is not the other party, it's the system that causes there to be only two alternatives that are both captured by mostly the same interests. Each party convinces half the population that the other is trying to destroy them so that their votes cancel out.
The con is largely directed at the religious right, of which, poorer whites make up the largest cohort. That's how they convinced people directly targeted by the bigotry to still vote for them.