Nobody is born knowing how to instruct / teach others.
I suppose that's why there are teachers' colleges and institutes. And, doubtlessly, they produce some excellent educators.
At the same time, most of us won't need to know education history, theory, or philosophy in order to share our know-how with others.
These things certainly have their place and purpose, but they aren't very useful if all I want is to show someone how to do something that I happen to be good at.