This is just a "logical" guess, not a scientific opinion from a well respected source..
If you bury your dead, scavengers can't get to them..
If scavengers can't get to them, they don't "learn" to acquire a taste for human flesh..
It does not become a recognized part of the scavenger menu..
Couple this with the dangerous nature of an armed human, or worse, an armed group of humans, and scavengers ( and predators ) begin to develop an "aversion" to humans, whether singly or in groups..
You don't want hyenas to develop a "taste" for you, or your family, or tribe.. ( except maybe Mukoo.. He's a jerk and steals your food sometimes..)
And sometimes Hyenas don't wait until you're dead.. A hungry Hyena will attack if you're alone, and weak, and seemingly defenseless..
Likewise with predators.. once they learn that humans are easy prey, human becomes the "snack de jour"...
Human is much easier to hunt than antelope.. It may not taste as good as pig, but pigs have tusks and can hurt you..
Choosing prey is a learned behaviour for both predator and scavenger..
Burial is a logical action encouraged by self-interest..
From 120,000 to 60,000 years ago, our ancestors existed nearly 100% as beachcombers along the shores of east Africa and southern shores of Arabia and Asia. Perhaps they started the habit of burying the dead to keep from feeding the sand crabs?