Caste hierarchy gives every group a stake in preserving the system.

Evidence

The second reason why I say the task is impossible will be clear, if you will bear in mind that the caste system has two aspects. In one of its aspects, it divides men into separate communities. In its second aspect, it places these communities in a graded order one above the other in social status. Each caste takes its pride and its consolation in the fact that in the scale of castes it is above some other caste. — Ambedkar, B R, Annihilation of Caste_ The Annotated…, 972

Categorization

• XREF: Connects to the graded-sovereignty argument Ambedkar develops in the next paragraph and to broader theories of divide-and-rule hierarchy. — connects to: Caste labels perpetuate hierarchy because names carry fixed notions of birth-based rank.; Abolishing sub-castes may actually strengthen and entrench the larger castes.; Radhakrishnan defended caste as affirming the diversity of human groups. — Ambedkar, B R, Annihilation of Caste_ The Annotated…, 1138 (+2 more)
• corroborated: 2 independent passages support this claim — Ambedkar, B R, Annihilation of Caste_ The Annotated…, 972