Yeah, there's an ongoing debate in biology right now regarding teleological descriptions of evolutionary phenomenon. Like rewording sentences like "a bird's wings are designed for flight."

Also in regards to the uncanny valley, I really doubt whether or not we see something as partially or fully human is some kind of pure, instinctual, hardwired thing in our genetics crafted over eons specifically for survival. It's probably a combination of learned social cues and however mirror neurons work to generate the emotion of sympathy. So the whole hypothesis boils down to some people get creeped out by human-like things that look weird. Ok, yeah? Weird things look weird? You don't say. Thanks, science.

Not everyone has the same idea of what looks weird and it certainly can't be consistent across generations and cultures. My mother in particular cannot look at anime characters because they freak her out in a way that seems to be an uncanny valley effect. I despise how Pixar characters look and move their faces, but those movies are huge so I'm clearly in a minority.