Not identifying your target as a gobbler is not an accident.
Exactly.
Then beyond that, just what about a human head resembles a turkey's head?
I'm coming from the perspective that this so-called hunter was not in fact shooting at a real turkey, and the hiker was unfortunately in the background unseen. That would be quite a stretch, but more in line with accidental than purposefully negligent & stupid.
I have had a multiple experiences where game was between me and another hunter, and had either of us shot at the game between us, could have been one of us dying.
One of the closest calls I ever had, and it was on private property, was when a squirrel ran down the side of a tree, I almost shot him, but noticed another hunter (previously unseen) only about 15 yds away, and he was about to pull the trigger on that same squirrel. We were both pointing our shotguns right at each other, each of us seeing each other simultaneously.
Just saying, true accidents
CAN happen.