This matter in "Shuidiao Tou" refers to

The thoughts and feelings expressed in this word are very obvious. Due to the political frustration and separation from his brother Su Zhe, Su Shi felt a sense of oppression in the Mid-Autumn Festival. However, he did not fall into a negative and pessimistic mood, immediately eliminated his worries with transcendental philosophical thoughts, and finally showed his love for human life.

On the surface, this incident refers to "people's joys and sorrows, the ups and downs of the moon", but in fact it refers to their own political dissatisfaction.