I will never understand why soy farmers, a huge majority of Midwest farmers, would be in favor of annoying China, the number one purchaser of soy. Granted I also don't know why they make fun of soy when it drives their economy.
If you're referencing the bar graphs towards the end, I think that's more explained by considering the full tonnage sent vs specific industries. In a paragraph or two before them, it shows exporters are worried about more expensive goods being prioritized. People are also presumably buying up what they can in case it gets worse. So tonnage may be similar still, but specific goods may be down and it may be a "false" baseline being shown currently.
They are related but only loosely. They don't use friendly language, e.g. "Waterborne containerized agriculture exports" is technically accurate but not as intuitive or useful as "American soybean exports" would have been if they had focused on something more tangible and specific.