@Bread I do think many perceive it as problematic or somewhat risky that mining is dominantly chinese. However, the insentives for both the chinese state and individual chinese miners to attempt an attack e.g. 51% attack is low. In the end it would cost them a lot of money since the crypto they own, e.g. Bitcoin will drop in value.
It is true China is becomming increasingly powerfull and influential e.g. they own a lot of mining and as such resources through mining in Afrika and they become increasingly influential in the South chinese sea. There are however also plenty of problems in China, e.g. looming property crisis, empty cities, hug debt and many banks are financially unhealthy. To much open conflict is not good for China since it damages their economy and opens the door for instigating internal division by foreign governaments. I am not only talking about devision by targetting minorities but also the fact that large parts of chinese population are still relatively poor and many rich do not have any nationalistic ideology, e.g. they care just about themselve. So all in all, lets not make China bigger or scarier in the mind than they are.
The problem is as @Paouky mentioned that it is hard/near impossible to limit mining in a region. E.g. newly mined blocks by a chinese miner can simply be relayed through computers outside china. Ironically, one of the best ways to avoid this dominance of mining in China is going green/state sponsored green energy production. Not exactly in line with Trumps plan for the US.
Anyhow, these are just my thoughts based on limited information and what I know from my 1 month trip through China and from Chinese friends. I did not read any book on it.