A Nobel physicist that couldn't do basic arithmetic would definitely raise my eyebrows, but even taking your analogy at face value Gemini was not marketed as fast food slop. Google can't be trusted to hype products in a reliable way, regardless of their technical details.
It's trendy for accomplished people to talk down about themselves as a way to sound cute. It's similar to software developers who like to say "I don't know what I'm doing, I just Google and Stackoverflow all day." It has a certain charm to it, and certainly there are some people for whom it's true, but overall it's just a misguided attempt at being modest but ultimately a horribly misleading statement.
"Do not worry about your difficulties in mathematics, I assure you that mine are greater" - Albert Einstein