No, it’s not sarcastic. I know that I am ultimately responsible for spelling errors, but spell check isn’t all that helpful IMO. For me, it almost always picks something I didn’t mean. If it isn’t useful, why does Apple provide it and not allow the user to turn it off? I almost always check my spelling anyway because spell check is wrong so often. Sometimes I forget, and there’s that stupid error, often from spell check, staring back at me.