That's unnecessarily rude, and untrue in any case. Everyone has to learn stuff sometime, and most people won't naturally run into the implementation details of how higher level languages get translated into machine code.
I agree his tone was not productive but the comment he responded to seemed like a disingenuous argument as well. "The CPU doesn't know about that stuff" is not true -- or it's arguing in bad faith. I mean, hello, tagged unions, all of us with some experience can write a C program that works with those. It's 100% false to say what he said.
