Cross-platform public judgment in a cultural heritage crisis: A topic modeling study of the Nanjing Museum donated-artifact controversy

Crises involving cultural institutions increasingly unfold across multiple platforms, where the same controversy is interpreted through different content formats, interaction structures, and community norms. This study develops distributed accountability as a function-based framework for examining how public demands for sanction, explanation, and relational repair are organized across platform environments. The study analyzes 64,349 publicly visible top-level comments from Douyin, Bilibili, and Rednote, organized into three event-anchored source-content groups concerning the Nanjing Museum donated-artifact controversy. BERTopic identified 49 substantive topics covering 42,126 comments. A higher-order thematic framework was subsequently applied and validated by two researchers, producing six substantive groupings mapped onto punitive, knowledge-based, and ethical accountability functions. Under the primary coding specification, ethical accountability accounted for the largest share of classified comments, although this absolute ranking was sensitive to the treatment of the largest disputed topic. Across event-anchored groups, donation ethics was relatively more prominent in discussion attached to the initial response. Investigation-oriented and personalized-blame themes were relatively more prominent in later groups. Cross-platform differences were more stable. Douyin showed a relatively stronger punitive profile, and Bilibili showed a relatively stronger knowledge-based profile across alternative coding specifications. The overall platform–function association remained small. These findings indicate that platform differences concern the relative organization of accountability discourse, not the presence or absence of particular accountability functions. The study extends research on platformized public judgment and institutional crisis governance by showing how functionally differentiated accountability demands coexist within a shared institutional crisis.