Whoever told you that just doesn't want you to come out to mule deer hunt. ;-)
It is completely how the meat is cared for. Way back in the day (old B&W photos) guys would drive all over with a deer strapped to the hood of their car for days. One time I stopped to talk to another antelope hunter in Wyoming and he had two does in the back that were bloated out like balloons. Can you imagine eating a beef after treating it that way?
My dad taught me to be meticulous in caring for venison, and I'd have to say I've never eaten a bad deer, moose, antelope, sheep, caribou, mountain goat, elk, etc….