Are you unfalmiliar with how the Israelites turned the brass serpent into an idol?
Nu 21:8 And the LORD said unto Moses, Make thee a fiery serpent, and set it upon a pole: and it shall come to pass, that every one that is bitten, when he looketh upon it, shall live.
2 Kings 18:4 He removed the high places, and brake the images, and cut down the groves, and brake in pieces the brasen serpent that Moses had made: for unto those days the children of Israel did burn incense to it: and he called it Nehushtan.
People can make an idol of anything, even those things that God himself has declared good. Even the cross. Consider the crucifix that so many worship.
Hank