The point was not about your skin colour but your ideology - "some people are just better because nature".

To put your example in different terms - I don't have the physique of an olympic athlete, so I'll never be that fast or strong, but going to the gym absolutely improves on what I have already. I don't have to just live with whatever nature handed to me.

That's a false equivalence and you know it.

The fact that you can somewhat improve your muscles doesn't change that some people need to put much less effort in or can recover fast enough to be able to put more effort in.

Same for brains. Except we don't know a way to improve a healthy brain's performance (*in a general way, ergo a way that transfers to other tasks).