this is a nothing. the list it produces first is not exhaustive. there are no contradictions or falsehoods here, and what you observed in this post is barely ambiguous. humans may be categorized among the great apes, but are rarely referred to as such except in relation to the other great apes. Otherwise we tend to be extremely chauvanist and just call ourselves humans.
this is like "what are animals"
and it produces a list of birds and reptiles and fish and mammals but doesnt include humans. and then you ask "are humans always considered animals" and post a gottem.
Great apes are closely related to humans BECAUSE humans are great apes. That idea is offensive to many religious zealots, so it's not a fact often brought up in any conversation unless specifically prompted. This isn't a logical fallacy you've uncovered, just a cultural bias and stigma. Of course a language model will also avoid the topic unless specifically prompted because it's trained on people and articles that ALL do the very same philosophical dance and mental gymnastics to avoid inciting the ignorant zealots.