Earlier quoted context omitted.
When faced with a choice between: - causality is less widely applicable than we like to think - our behavior is more complex than we like to think I'm more inclined to doubt causality. Not that it's not a useful framework in general, but that is less useful when applied by humans to humans regarding human constructs like kindness.
This seems unclear. I mean, either X causes Y or it doesn’t. (If you change X, holding everything else constant, does Y change or not?) One thing you might mean is that causal chains are very complex and variable, so the average causal effect in a large population is not very informative about any individual - it’s an average of many different sized effects.
As for your first paragraph, I don't think you can reasonably treat causation like an everywhere-binary like that. Not for arbitrary choices of X and Y.
Take "hunger" and "war" for instance. There are many causal arrows pointing from war to hunger, and several pointing the other way too. You have to zoom in to specific details before the language of causation starts being useful. "good for your health" and "being kind to others" are similarly aggregate concepts.
Causation is a myth, and a damn good one. We use it to reason about nearly everything. But the tendency to use it to reason about actually everything is a dangerous one.
Most of the time you can't "hold everything else constant". We usually have to settle for frobbing X back and forth many times and letting its continued correlation with Y convince us that there is indeed causal wiring between the two. At the end of most experiments is an inductive leap of faith that is justified by the high frob cout.
But sometimes X doesn't go back and forth. Sometimes it's a one-way deal and you only have one of them. Like maybe X is "finding carbon trapped in the earth's crust and releasing it into the atmosphere", and Y is "a global change in climate that poses an extinction risk to humans." In cases like that, we don't have the luxury of waiting for enough induction to bring about the leap of faith.
The situation with kindness and heath is similar. Ideally we'd take whatever wisdom we can from the correlative data that was presented and run with it--maybe there's a cause in there and it would make us healthier, maybe not. Instead we have this artificially high bar for argumentative strength, and when an argument fails to meet it we throw the baby out with the bathwater.