I think it’s this. If somebody destroyed your cross, would you be fine with it, upset because something you worked on was destroyed, or upset because something you revered was destroyed. If it’s the first two, you’re fine. When you start to revere the religious items beyond what they represent from an artistic perspective, that’s when they become idols. Similarly, you could revere an ancient Christian relic for its rarity, and be upset that something so rare was destroyed. As long as you don’t worship the item itself, it remains only an appreciation for artistry or rarity.