I think such statements can serve a purpose. It is a gesture to show the rest of the world that China can act mature and conciliatory, leaving a way to de-escalate tension even if the US doesn't take it. That can help build more goodwill among the Global South nations. It's not about trying to sway the majority opinion in the West anymore.
However even within the West, there are some groups like businessmen or other interest groups that do not want to see more escalation or outright war. Such gestures help them oppose further attempts by the US government to escalate, and it also tries to divide opinion so that there is not unanimous resolve within the population to unite in opposition to China. If China acted like the implacable existential threat and hostile bogeyman that the xenophobes are trying to portray it as, then these more moderate people would also turn against because they would feel threatened themselves.
Basically I think it follows Chinese strategies of not closing off all lines of retreat for the enemy. If they are cornered and surrounded they will unite and fight even more fiercely. If they have a way to back down or retreat, then their resolve for an existential fight will be weaker and they may either not escalate to a fight or be more willing to cut and run when there are setbacks.