Final Answer:
The South Vietnamese began to support Minh due to his role in overthrowing President Diem in a coup.
Step-by-step explanation:
South Vietnamese support for Minh stemmed from his involvement in the coup that overthrew President Ngo Dinh Diem. Dissatisfaction with Diem's leadership, characterized by political repression and social unrest, led to a coup in November 1963. General Duong Van Minh, also known as Big Minh, played a key role in this coup.
The removal of Diem was initially met with some optimism, as it was perceived as a step towards political stability and reform. However, Minh's subsequent leadership faced challenges, and the political situation remained complex and unstable in South Vietnam.