...or is it mere propaganda such as the "threat" that Afghanistan, Iraq, Russia, and Grenada, etc. etc. etc. posed upon us?
'Us' being western industrialised nations.
China is no more threat to us, than others are to them.
It's the usual political power struggle, where countries want to push their own agenda/political ideas upon others.
I think the way you can look at it from an overall point of view, is you can look at different countries and ask whether you would want to live under those circumstances. If the answer is no, then that country is a potential threat to what you consider best. Obviously, the majority of countries don't have the influence that the US, Russia and China have. So it might work on a smaller scale as well. For instance, Denmark is very connected and influenced by Germany, simply because they are bigger and we trade a lot with them. If we imagine that Germany and the US had a serious fallout, then a country like Denmark would probably be greatly affected. Just as a lot of countries bordering Russia are heavily affected by them.
But these massive economies influence on a much larger scale. So it is also a struggle of ideologies, in the west we tend to value freedom of speech etc. Which as far as I know, is not valued very high on China's scale.