It's not just the worship of idols. It's the substitution made where you put yourself in God's place.
One better known form of it, but less understood, is the "What Would Jesus Do" phenomenon. Jesus as Lord, told you the standards that you are supposed to use. Where He has spoken, substituting your judgment for His is, in fact, idolotry.
To ask what Jesus would do (and then woodenly carry it out) certainly seems to miss the fact that Jesus was special with a special mission. Yet, to call God an idol is a paradox at best, great blasphemy at worst.