Maybe in terms of ultimate "responsibility" but this is a really simplistic view (in my opinion).

It'a unlikely that every piece of information was reviewed by a human... More likely that large data sets were identified, but the actual data is unknown.

The training is probably based on several layers of AI networks and algorithms, and, again, unlikely that any human is doing the actual "regulating". Humans involvement I would guess is about the algorithm selection and data set selection, including developing an AI/algorithm disclaimer and censorship. But curation by humans is probably an overstatement.