Read Isaiah. What does it say? Pierced for our transgressions?
No one was pierced... The verse, referring to Israel, says:
53:5. But he was pained because of our transgressions, crushed because of our iniquities; the chastisement of our welfare was upon him, and with his wound we were healed.
Pained, not pierced.
I still won't be so crass as to say that you are lying, even though I think you are being dense.
Read Numbers 21:9. Was the bronze snake looked at in the same way that the golden calf was?
The bronze snake was an interesting idea that misfired, and when it was being wrongly used, Hezekiah fixed the bad judgment by melting it down.
It was supposed to be used as a learning tool. We were supposed to have grown out of its use, especially when it was so easily abused. (Funny - many Christians say that about the concept of the commandments. And now Jesus is supposed to fill a similar role? Maybe anyone is supposed to grow out of the use of Jesus as a focusing tool. Hmm...)
Jesus is supposed to have said "None can come to the Father but through him."
That is idolatry right there.
People were supposed to look up when they saw the snake and think of heaven, and think of God.
But you know... Tzitzit are supposed to remind Jews to think of the water, of the sky, of God...
All without an idolatrous image.