I do think that people are sometimes confusing "transient shortages" with like, well, starvation.
Not having fresh kale (or spinach, or oranges) available for a few months isn't going to kill anyone. I think, if anything, most people are going to be potentially inconvenienced at the grocery store, and not a lot more. However, if you have to live on a diet that is mainly fruit and veg, you're going to be seriously impacted if there are shortages of those items unless you've made provisions for them (aka frozen or otherwise preserved). It's not unreasonable to cover one's backside. Especially in those circumstances.
My own main concern is less inconvenience and more the price for foods. I've got a nice larder stocked with stuff I would have bought anyway, and purchased on sale. As we all have no clue what the fallout really will be, I'm protecting my purse as much as my stomach, at least for a while, in case food costs do rise. (I'm not convinced that if they rise they'll go back down again anytime soon.) If it's not all that bad, well, I would have bought this stuff anyway, and we'll just continue to use it as we have been doing.
Pharmacuticals are more worrying. Thankfully, we have a stash of what we need from our trip to the USA recently that will last us until we get back there again, if needed. I kind of wince for people who have to take medicines that cannot be stockpiled. That's the kind where shortage can have really nasty repercussions. The little blurbs of info that are filtering down to my ears are that there's some real concern about that supply chain. Fingers are crossed it's inaccurate.