Wikipedia lists theomorphism when humans are attributed with divine traits (ie: “In His image, He created them.”), but that’s all I can find for that matter.
Anthropocentrism seems to be the word I’m looking for, but I don’t know if it has quite the right nuance.
Tom-A-to, tom-ah-to. It is a descriptive action. “Denying [human] traits” is functionally indistinguishable from assigning non-human traits. “He is emotionless”. “He lacks emotion”. Both statements are dehumanizing.
Religion? 
Joking aside, you might accuse them of Speciesism. I am not a fan of the word, but it does appear to be gaining acceptance. Human exceptionalism is another option.