How does this follow?

There's nothing "basic" about Calculus II. Calculus is uniquely cursed in mathematical education because everything that comes before it is more or less rooted in intuition about the real world, while calculus is built on axioms that are far more abstract and not substantiated well (not until later in your mathematical education). I expect many intelligent, resourceful people to fail it and I think it says more about the abstractions we're teaching than anything else.

But also, prompting LLMs to give good results is nowhere near as complex as calculus.