WHAT "natural fear of humans"?
A coyote who comes into a human back yard can be assumed to not have much fear of humans. Why should it? Humans are not especially fast, don't have sharp teeth or claws, and don't have sharp senses. There is nothing "natural" about coyotes having fear of humans.
Coyotes, in generations passed, have become conditioned to stay away from humans, in the days where being seen by a human would earn one a bullet. I doubt if this fear has made it into the DNA, though. And now that a coyote can come within a few yards of a human without bad consequences, and human habitations are a rich source of easy food (whether backyard poodles or overturned garbage cans), any conditioned intergeneral fear is about gone.
A coyote may be wary of an alert adult human, purely because of the human's larger size. But a human infant without an adult near it? Easy dinner