Song Zhentao was also a Municipal Party Secretary, holding a significant amount of power, even though his status still fell short of Su Mengxin's, but it wasn't so much that whatever Li Yifei said went. That said, with Huaxia's increasingly intense anti-corruption campaign, being a secretary meant being particularly sensitive to such matters. With Wang Hongmin indulging his daughter to such an extent, if this was to leak online, it wasn't just Wang Hongmin who would be unlucky—there would be significant pressure on the whole municipality.
Li Yifei sending the video directly to him was a way of saving face for him, enabling him to deal with the situation directly without causing a national uproar that would be difficult to contain. Therefore, he immediately made a decision.