I think the main idea is that the colonial state is going to wither away on its own because zionists are already leaving due to how unsafe it is for them to be there, and by the time a two state solution would be implemented, this will have already reached a point where those people will not return and anyone like them who remains will want to leave even more because they have had their colonial project taken away. This will lead to an inevitable one state for Palestine because all the euros will flee and Palestine will have a majority and keep gaining power in the area, while the colony is fully weakened, loses a lot of population, and by then maybe even a lot of external funding.

China having this position makes sense because they are trying to be taken seriously as a mediator and the two state solution is the closest thing to a good deal for Palestinians that is actually being considered at the moment, but the average communist position should absolutely be an end to the zionist state entirely. If China adopted a one state policy in favor of Palestine, they wouldn't be included in any serious negotiating because that is obviously not something one of the parties in the negotiation wants to accept at the moment.