I question the same things frequently. I routinely try to ask chatgpt to help me understand the openai api documentation and how to use it and it rarely is helpful, and frequently tells me things that are just blatantly untrue. At least nowadays I can link it directly to the documentation for it to read.

But I dont understand why their own documentation and products and lots of examples using them wouldn't be the number one thing they would want to train the models on (or fine tune, or at least make available through a tool)