Agree that food is not an issues anymore from China, but remember that China import the majority of soy bean even I know most of them is for animal feed.
Food/agriculture is a strategic industry, China must protect them and keep the 95% food self-sufficiency ratio intact. When a crisis happen, nobody would export their food to anybody (which is understandable), including of course the USA.
About a month ago, Vietnam banned all rice export ... if you relay on rice import from Vietnam, you would be in big trouble. Thats why Japan want to have domestic rice still intact, even probably 5x more expensive than international price and Japan very much ~100% self sustain in term of rice.
Singapore, Hongkong, Middle East countries, some African countries and some others would be in big trouble if we had big crisis that no grains/foods can be imported
Japan’s food self-sufficiency ratio on calories basis was 79 per cent in 1960 and had declined continuously reaching 39 per cent in 2015
China's overall food self-sufficiency is likely to fall from 94.5% in 2015 to around 91% by 2025
I think 91% food self-sufficiency for China would still be fine, as there are still the strategic grain reserves.
Plus in a real emergency, they can cut out the wastefulness and increase production, so that there will be more than enough.