I wonder if the difference in experience could come down to the specific circumstances and nature of the issues that someone faces?
/sarcasm, but I've seen serious versions of this argument
I don’t know what ‘people have different baseline biochemistry’ really means. Approximately zero humans survive on sulphur and chlorine in place of nitrogen and oxygen. This argument tends to overlook the fact that people are mostly similar, and there’s enough of us that we have decent data on how similar we are. Humans are all approximately the same construction, and have approximately the same reactions to most things. It’s true there’s tons of minor variability for some things, but no serious science or health advice that will fail to mention or acknowledge that variability. My advice (which may or may not work for you) is to ignore people who say health advice must fit all people… and also ignore people who say that no advice will work for them, or even that advice that works for most can’t work for them without trying it first.
I feel like a good default assumption is that something that works for the average person will probably work for me too, so try it first, and then look for alternatives if/when I find out it’s not working. This is still a good default assumption even when accounting for the ‘flaw of averages’ (cf. the Air Force story about cockpit design) - most of us will fit the the average for most things, even while at the same time most of us will be outliers for some things.
I keep seeing people take statements that are valid within reason to the extreme.
In broad strokes, most things about humans are true, but there is certainly nuance and variation between people. Probably because we don't fully understand the things we think we do.
Isn't that what the vaccine is for?
It's still a good idea to not step on dirty rusty nails. There are no exceptions here.