“The two wire witching technique is reacting to the magnetic properties of the minerals in the water or metal pipes or under ground wires.”
Any magnetic properties would be too weak for a wire to react to even when directly next to water with minerals in it, but especially through several feet of earth. And it wouldn’t explain how wood sticks would work.
I just did it in my garage and those two wires reacted to an iron I-beam that was five feet over my head, and then tried it walking over a 50 lb iron dumbbell where again the two wires crossed. It works.