Is the "gamey" taste of venison just a polite name for "rotten"? I have had a theory for a long time that it is the blood in the deer which causes the gamey flavor.  Hunters gut the deer soon after a kill, but they don't bleed it or chill it for hours or days.  It takes time to haul it from the woods, then drive home and wait until the next day before visiting the processor.  It seems that the blood would be the first part of the animal to spoil.

It is my opinion that the bad reputation of venison’s “gamey” flavor comes from poor processing habits and the serving of meat that is actually rancid or at least borderline.
The key to fresh tasting meat it to get it cool and skinned as fast as possible.  Leaving it hot or leaving the hide on will cause it to rot quickly and leave your meat tasting quite “pungent” (i.e.: rotten).  This is important whether you plan to butcher the animal yourself or are taking it to a pro.  If you leave the hide on longer than necessary or don’t cool the meat quickly, it will have a bad flavor.

http://lazyhomesteader.com/2012/08/21/the-gamey-taste-of-game-meat-part-ii/
Is it true that the gamey taste is caused by spoiled blood in the meat?
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.