Please don't take that the wrong way, I am not comparing you to anyone that is a anti-hunter.
Not at all, and your opinion and questions are well justified.
If the size of the wound channel was the only issue, using a broadhead that causes a large hole (wound) to kill a deer is an individual call. If avoidable, I personally do not like to blow an overly large hole in the cape, and I do not like to destroy too much the meat or cause a lot of bone fragmentation. However, that is a "housekeeping" preference. My issue with using heads that have a cutting area grossly larger than need be, and cause wound channels greater than need be to be lethal, goes beyond the "housekeeping" aspect.
As I said, you do not have to blow a huge hole through a deer to be a lethal hit. Nor does a large wound guarantee that death will be immediate or imminent, that the animal will be recovered before it dies days later from other causes caused by a grave wound.
I consider myself a good shot, but I know that once I release the string, or just at the moment I have reached a point of no return as I am about to release the string, anything is up for grab. If the hit is off and the wound is not lethal within the time and distance that gives the greatest odds for recovery; I now want the odds in favor of the deer that he or she might recover.
Anyone that claims to be so good that they never miss, believe they will never miss, and claim that all of their hits have always been in the exact spot having the greatest odds of lethality, and therefore using a large cutting broadhead that causes extensive wounds is a moot consideration for them, also sells snake oil.
When compounds became popular, they (compound bows) put many bow shooters in the field who did not belong in the field. Then the along came compound bows with greater energy and high letoffs, which caused the inexperienced and the "speedsters" to believe that arrows now fly so fast and the trajectory is so flat they can now take shots at distances that would challenge some firearms. Now we have mechanicals that fly like fieldpoints, which has diminished the tuning skills of many shooters.
The sport sure does not now need to introduce a broadhead that will develop a mentality in the fair-weather and "quickie" hunters that the broadhead is so devastating that all they have to do is just hit the animal anywhere and it will die on the spot, or within minutes. You think not?
I would ask this question back to you. What type of broadhead are you talking about?
A sharp one shot from a well tuned bow and accurately placed in the common kill-zone.