Long time thread it looks like so I better get in on it! Everyone is entitled to opinions and we get to express them on here, so thanks to Huntingnet forums for that!
I believe that a .223 is an ethical deer hunting cartridge. You must be a little bit choosier with your shot selection and a lot more careful with bullet selection. I would never take a shot at the shoulder with one, but a lung shot is perfect for that caliber. I do the same thing archery hunting, I do my best not to put my arrow through their shoulder, but a bit behind it into the lungs because I use expandable broadheads. It is the same idea, you put that bullet into its lungs and heart, it will drop that deer.
A well placed .223 is better than a .338 Winchester Magnum in the deer's haunch!