Visual social media platforms have become primary venues for political discourse, yet we know little about how moralization operates differently across platforms and topics. Analyzing 2,027,595 TikToks and 1,126,972 Instagram posts during the 2024 US presidential election, we demonstrate that issues are not necessarily inherently moralized, but a product of audience demographics, platform architecture, and partisan framing. Using temporal supply-demand analysis and moral foundations scoring (eMFD), we examine the dynamics of key electoral issues. Three key findings emerge. First, moralization patterns diverge dramatically by platform: TikTok's algorithm enabled viral spread of moralized abortion and immigration content despite lower supply, while Instagram amplified economic discourse that aligned supply and demand. Second, traditionally "pragmatic" economic issues became moralized-cryptocurrency discourse invoked loyalty and authority foundations more strongly than any other topic, framing regulation as government overreach. Third, platforms responded to different events: TikTok surged after Harris's nomination across all topics (96% reduction in supply volatility), while Instagram spiked around cryptocurrency policy developments. Semantic network analysis reveals TikTok's circular topology enables cross-cutting exposure while Instagram's fragmented structure isolates Harris from economic discourse. These findings demonstrate that understanding political moralization requires examining platform-specific ecosystems where architecture, demographics, and content strategy interact to determine which issues get moralized and how moral content spreads.

翻译：视觉社交媒体平台已成为政治话语的主要场域，然而我们对于道德化机制在不同平台与议题间的差异仍知之甚少。通过分析2024年美国总统选举期间的2,027,595条TikTok视频与1,126,972篇Instagram帖子，我们证明议题并非必然具有内在的道德属性，而是受众人口结构、平台架构与党派框架共同作用的产物。运用时序供需分析与道德基础评分（eMFD），我们考察了关键选举议题的动态演变。研究得出三项核心发现。首先，道德化模式因平台而异：TikTok的算法尽管内容供给量较低，却促使道德化的堕胎与移民内容实现病毒式传播；而Instagram则放大了供需匹配的经济议题讨论。其次，传统上“务实”的经济议题被道德化——加密货币讨论比任何其他议题都更强烈地唤起了忠诚与权威的道德基础，将监管框架塑造为政府越权。第三，平台对不同事件的响应存在差异：TikTok在哈里斯获得提名后所有议题的讨论量均激增（供给波动性降低96%），而Instagram的活跃高峰则围绕加密货币政策进展出现。语义网络分析显示，TikTok的环形拓扑结构促进了跨议题的交叉曝光，而Instagram的碎片化结构则将哈里斯与经济话语隔离开来。这些发现表明，理解政治道德化需要审视平台特定的生态系统——其中架构、人口结构与内容策略相互作用，共同决定了哪些议题被道德化以及道德内容如何传播。