The Short Version
The claim captures the substance of Sun Yat-sen's Minsheng doctrine accurately but oversimplifies its development. Multiple academic and primary sources confirm that Sun equated Minsheng with socialism, rejected class struggle, and proposed land equalization and capital regulation as policy pillars. However, the relationship between Minsheng and "socialism" was notably ambiguous and debated among scholars, and the implied neat chronological sequence of "stated equivalence → later clarification" compresses a more complex, evolving ideological trajectory spanning decades.