Take this with a grain of salt because I am not autistic but my first intuition when reading the paper wasn't that autistic people antropomorphize objects, but maybe its the other way around. Namely that they have less of a subjective or interior view on people, how other people see them and maybe how they see themselves (there's some comments to that effect in this thread)

Again because I don't have direct experience with it I don't want to lean too much into stereotypes, but it seems possible to me that people with autism have a more monistic, or at least less dualistic view on these things because the kind of thing that makes other people distinguish between subjects and objects is less present in people with autism.