"but as soon as people start performing physical acts of worship towards the artwork, it becomes an idol"
Sorry to contradict, but your oversimplification of the matter has led you to an incorrect conclusion.
One must distinguish between kneeling *to* a statue and kneeling *in the vicinity of* a statue.
Idolatry consists in kneeling *to* a physical object for the purpose of worshipping it. Kneeling *in the vicinity of* religious art so that one may gaze upon it while praying is not idolatry.
Another distinction you fail to make is that not all prayer is worship. In Elizabethan times, the word "pray" was widely used in conversation to make a request of another person, as in, "I pray thee, Lord Cromwell, slay us not for our Catholic faith."
Or perhaps, "Prithee, good wife, pray for me on the eve of battle."
Catholics ask (pray) saints to pray for them in the same way that protestants ask (pray) their fellow protestants to pray for them. The only difference is that protestants, having cast about half of God's blessings back in His face, don't understand that the Communion of Saints allows them to ask saints to pray for them.
And one can plainly see both in the picture I've provided earlier in this thread and in the quote from post 336 from a Catholic website that Catholics do indeed bow to statues.
I'm not even getting into the prayer issue; it's tangental to my point here, which is that your denomination violates the specifics of the Second Commandments. However, having said that, I've read many of the Catholic prayers to Mary, including the one at the end of the Rosary (see post 105), and they are worshipful, and attribute to her the things that belong to God alone.