No. He is talking about irony, not sarcasm. Irony is typically understood to mean saying A while being aware (or of the opinion) that !A. Viz. "Nice hat, dad",

No. He is talking about irony, not sarcasm. Irony is typically understood to mean saying A while being aware (or of the opinion) that !A. Viz. "Nice hat, dad", or "Real good idea" (when it's not). Sarcasm (cutting remarks) often involve irony, but not always; it's an orthogonal concept. Also, dropping the "not" in "Could not care less" is not reasonably said to be a grammar mistake. It's usually not sarcasm, either. Whether you agree that it's irony is a different matter (I'm pretty sure it's not).