The idol is found in Unitarianism, when they deny the deity of the Savior, seeing Him as a creature like themselves made of the earth and bound to the earth, and then worship Him.
I am well aware that since the Bible tells us that every knee shall bow (a word translated from the Greek that in the Greek is reserved for deities. The Greek is much more nuanced than English) at the name of Jesus and confess that He is Lord (God) the Unitarian claims they do not worship Jesus as God. You can deceive yourselves all you want, but God knows exactly what you are doing.
The doctrine of the Trinity IS unique to Christianity. That is one of the things that MAKES it Christian. So any religion that denies that is NOT Christian. To call a religion Christian that denies the Trinity is a deliberate, and in many cases, maybe originally, deception. The spirit of anti-Christ. You can't get around the historical facts or the Word of God.