I have to agree with this to a point. A bigger cut in the vitals will usually down game quicker and give a better blood trail. But anything, even a field tip, that takes out both lungs or heart will kill any animal. The problem comes with hunters not matching the broadhead to their set up. I shoot a PSE DNA at 63# and 29" DL and I shoot Rage Hypos now. Prior I shot a Martin Cheetah at 60# and used Slick Trick Razor Tricks or Magnus Stingers because of the cut on contact design. Now my daughter-in-law I have set up with her 40# Martin using Slick Trick Viper Tricks or Muzzy Phantoms.
My point is that light draw weight and big expandables do not go together. You need sufficient speed and weight to drive these into the vitals.