You've got a strong commitment to certain target bullets being used in hunting applications. One cannot deny you, you've proven through field tests that certain so-called target bullets actually perform just as well if not better than bullets designated as hunting bullets. I think the key to this discussion is having both sides of this argument admit that there is no 100% foolproof bullet that addresses all hunting applications.
One of the key elements which you've stated in your arguments is that shot placement is paramount. Take any bullet and miss the killing zone and it really doesn't matter what your shooting. At the same time, put any bullet design and hit the vitals and nine times out of ten, you're going to have positive results.
If you're an excellent shot and certain bullets perform better than others by hitting the kill zone, you're going to have consistent success. At the same time, if you're an average shot and shot placement is not always optimal, you're going to have compromised results. I think the difference with target bullets and hunting bullets is that when using the hunting bullet, somewhat marginal shots will result in a kill nevertheless whereas target bullets tend to give results that are more black and white. A shot that's not on target will result in nonlethal hits.
There are no one fits all solutions, in short there are going to be more gray areas than simple black and white solutions. Choose your bullet wisely based upon your hunting situations and individual skills. If your not certain as to what bullet is best for your personal application rely on the manufacturers recommendations.