Whilst that is true, I feel that if that human is an educator employed by a reputable institution, answering questions in their field, the expectation of most is going to be that they provide accurate information. As this is an introductory class, any arguments that even experienced teachers can occasionally cling to incorrect or outdated information becomes moot in my opinion.
LLMs as of now simply appear not reliable enough for an institution like this one to attach their name (which brings credibility in the eyes of the public), especially as their comments on the need for users to be vigilant ("they should always think critically when taking in information as input") make it sound like they did not in fact find some new way of reliably grounding output in accurate information.
Mind you, this is coming from someone who has great hopes for the future of LLMs in education as they can more effectively deal with students on an individual level. I just feel that currently LLMs are still too error-prone for an institution such as Harvard to incorporate them into an introductory course to assist. Until these insitution stop putting the majority of responsibility on students finding erroneous output, I feel this is not ready for wider educational use.