Is the "gamey" taste of venison just a polite name for "rotten"?
According to the University of Minnesota Extension (emphasis added):

What causes the wild or gamey taste in venison?
Venison refers to the
meat of antlered animals such as deer, moose, elk and caribou. The
'wild' flavor of venison is directly related to what the animal eats.
Corn fed deer will have a milder flavor than those that eat acorns or
sage. The 'gamey' flavor is more noticeable in the fat. Removing the
fat, connective tissue, silver skin, bone and hair during processing
lessens the 'gamey' taste. However, undesirable strong flavors are due
to inadequate bleeding, delay in field dressing or failure to cool the
carcass promptly.

So while some gaminess is simply due to the diet of the wild animals, improper dressing or treatment can be a contributing factor.