I think what you're failing to see is that a sentence like "math; not geology" sounds incredibly condescending and snarky. I don't know if that was your intent

I think what you're failing to see is that a sentence like "math; not geology" sounds incredibly condescending and snarky. I don't know if that was your intent, but if not it might be worth reflecting on what you meant to say instead, and why you did not notice that what you wrote instead comes across so negative. Because then there would be no need for heavy sarcasm.