We should understand this in a religious sense since any representation of God changes Him from what He really is. Egyptians worshipped oxen, heifers, sheep, goats, lions, dogs, cats, monkeys, ibis, cranes, hawks, crocodiles, serpents, frogs, flies, scarab beetles, the sun, the moon, the planets, the stars, fire, light, air, and darkness. And they could come up with "good" reasons why!
A young man once said to me that he could see nothing wrong with the Christmas tree because he did not bow down and worship it. He misunderstood. Do we? The first commandment covers this particular aspect of idolatry. If one was bowing down to the tree, that would be what he was worshipping.
The second commandment has to do with the way we worship, in spirit and truth. Christmas—and its trappings like the Christmas tree—is not part of the way God commanded we worship. It is not part of the truth of God. Therefore, the Christmas tree is a component of an idolatry created when man desires to worship God as he devises rather than as God instructs. So he breaks the second commandment even though he never bows down to the tree.