There are companies moving out of China to other Asian countries but it's not a mass exodus

Well, it can't be.

China is 1,400 million. Vietnam, 90 million, and so on. There simply are not enough local ASEANA workers to replace all in China to have a China+1 policy move a large percentage of the manu sector out of China.

As for not wanting to know how the rest of mankind thinks, the young and educated adults I have met (and taught in some cases), are much more aware of the wider world than certainly their parents or grandparents. But they have been told about the '100 years of humiliation' and it's still a sore point that cultivates extreme nationalism.

I think it to be a much older and more ingrained cultural habit.

In the 13th C. when Europeans first came to China, one of the things they noted was that the Mongols sent them to Qingdao to get a portrait painted. At first everyone was flattered. Then they realised that this was for security and tracking purposes.

Their xenophobia is as old as written records exist in China.

Mao and the USA and '100 years of humiliation' have nothing to do with it.

This is who they are, always have been.