Who ever told you that, most likely believes in "aging" their deer. The meat was most likely bacteria ridden when they processed it, and therefore they blame the fat, silver skin, etc and not their handling practices.
I only trim off the excess back fat and that's it. The silver skin, fat between the layers in the flakes, plates, etc and the connective tissue goes into my grinds. I have done it this way for my forty-one years in the meat industry and have never had a package turn "rancid." The sad part is that many hunters needlessly throw out more than they keep.
If the beef industry was to trim that way we'd be paying $10lb for hamburger or more!
Dave
