I don’t know the answer, but I wonder if it’s something to do with human feelings and motivations appearing inconsistent and being difficult to understand for autistic people. Anecdotally, my brother understands what emotions are and recognises them in himself and others, but he finds it difficult to understand why people react or feel differently from him. He has empathy, but he can’t always apply it; if I’m upset and crying over something he doesn’t find upsetting he’s like ??? By personifying objects he gets to imagine and practice empathy, without the vagaries of human emotion and individual differences muddying the waters.

I have nothing to base this on but my own experiences so I could be way off, but that’s my two cents!