Most however are surely capable of understanding a simple metaphor, in which "magic" in the context of coding means "behavior occuring implicitly/as a black box".

Yes, it's not magic as in Merlin or Penn and Teller. But it is magic in the aforementioned sense, which is also what people complain about.

Magic refers to specific techniques used in programming, an people generally dislike these techniques once they have formed any opinion.

Oh no! Reading!

Sorry for the snark but why is this such a problem?