I never claimed that idols must be tangible. Actually, I know no Christian who does. It is fairly well understood in the modern church that idolatry has to do with the veneration of things other than God. Money is perhaps the most common idol of the modern western world.

My claim is based on the fact that these statues and other iconography almost invariably wind up taking the place of God. The people who buy these sorts of religious icons (commonly referred to as "idols") wind up praying to the Virgin of Guadalupe, Saint Anthony, "the sacred heart", "the divine child", or whatever is depicted instead of praying to God. Such acts are idolatrous. Jesus didn't teach that you should worship his earthly mother, his friends, parts of his body, or his childhood. He taught that you should worship his father.

By the same token, the veneration of the boy Jesus can be a distraction from the veneration of the personhood of Jesus. This was expertly parodied recently in the film "Talladega Nights" where the main character prays to "baby Jesus" because he likes him better than the adult version. It's funny, but it's true; too many Christians are eager to worship the Jesus of the manger or the Jesus of the endless fish, but unwilling to face the Jesus who attacked the temple merchants or the Jesus who wept tears of blood while begging for his life. Jesus is Jesus and to focus in on just one aspect of who he is and was, especially one so poorly documented as is his childhood, can keep one from understanding the totality of who he is.