Questions always arise whether the use of Catholic Symbols is really a form of idolatry. Usually it is because the questioner is not altogether familiar with what these symbols really are. We do not worship the crucifix. We use it remember of Jesus suffering and death for the sins. We don't worship the fish. We display it as being a proud emblem of our Christianity. We do not worship the statues of the saints. We rely on them to point out their wonderful lives so they may be role-models for all of us to emulate.
Dating back to when the Ten Commandments were given to Moses, idolatry in the Old Testament was understood to be the worship of idols or images. It's the worship of not God that's wrong and sinful. The mere images, symbols or icons aren't the issue.
An excellent example of this within the duration of Moses may be the Brass Serpent. God commanded Moses to create this Brass Serpent and lift it high to cure any Israelite who checked out it of snakebites. Once more it was God who commanded Moses to create this image. Later in history, King Hezekiah destroyed the Serpent since the Hebrew people have been burning incense to it in worship. The symbol had eventually be an object of idolatry. See the difference?
When God gave commandments regarding idolatry he meant it to be understood in its most literal form. Based on the Bible, most idolaters really believed that their idols were gods. That isn't so today with Catholic Symbols.