Or it could be that Chinese audiences & tastes aren't so big on watching cheering crowds.
I am rather sceptical of this being evidence of censorship. Maybe, I could be swayed if it can be shown this is a clear break from tradition of showing crowds that started since the recent protests in china.
No one knows the future - but all we do know points that the future is far more optimistic than people realise. If Africa fails to reach 4.3bn then it will most likely be because of faster prosperity and not due to the pessimistic causes you mention.
To illustrate the point: The last 40 years have been the worst we will see in terms of stability, economic growth etc .... yet Population growth in Africa thrived and the % of people living in poverty reduced dramatically and the current population is healthier, wealthier, and more educated than ever before (https://ourworldindata.org/grapher/above-or-below-extreme-po... ).
In the grand scheme, HIV/Aids has not had a large effect on population growth in Africa (and unlikely to have for the future as it is a mostly localised to southern parts of Africa and has been coming down rapidly).