A pdf book from the University of Kansas. One has to ask whether foreigners (Soviets included) were hesitant to go into the communist regions, whether this was justified, and whether the CCP was wise or misguided in not appearing to be more open.
These are not trivial questions. A cynic could suggest that as the civil war progressed the CCP was uncomfortable giving the world a view of its actions in areas under its control. An apologist would point to the rough handling the CCP had received from the US and Brits and to the suspicion Stalin had earned for his agents.
I take a middle path. Mao was a latent xenophobe, was actively tapping the xenophobia latent in the nation, and it served the Party’s purposes to underscore that this was a purely Chinese revolution.
More evidence that the Mao and the CCP played the nationalism card better than Chiang and the Kuomintang.