I know some people are purists when it comes to stuffing the actual bird. After all, it's called stuffing, right?
The reason that is frowned upon these days is that during the butchering process, the cavity of the bird is exposed, making it susceptible to bad germs. To kill those germs, the temperature must reach 160 degrees inside the middle of that stuffing.
Basic science says that if you pack the cavity full of bread, by the time the inside is 160 degrees, the outside of the bird will be well above that temperature, drying out the meat.
So, do what you wish, but I prefer to bake mine in a casserole dish and save my guests the possible stomach ache.