Yes, they can. No, you can't force them to learn it in a practical way quite the same as you can, say, algebra. It's like teaching kids to paint. If you magically made everyone interested in painting most kids could become decent painters, but in real life they just aren't. Teaching a programming course to the general school population won't make 80% of kids capable of programming any more than compulsory art classes would make them into graphic designers.

I mean let's set aside the empirical sciences for a moment but mathematics is not just some weird set of rules that fell from the sky. It's designed by humans and for humans.

And for obvious reasons empirical models are also generally made to be understood by humans, though there at least you can argue that the underlying reality was not designed to be intelligible (and frequently isn't hence why we've got shortcuts like thermodynamics to reason about chaos).

Physical activity has existed since long before Homo sapiens. Do some people find it easy to participate in strenuous physical activity while others find it hard?

Why do you think that situation would be different for any other kind of activity that humans take part in?