I don’t have enough reputation to vote to close or migrate questions, so instead I commented on this question and wrote “This question is about math, not physics.” The comment was deleted. Was it wrong, rude, or otherwise inappropriate for me to write this comment?
The user posted essentially the same question twice, presumably by accident, then (correctly) deleted one of them. Your comment was on the other, nearly-identical question. (However, you will not currently be able to see anything by following that link—since you have to have 10k reputation to see deleted questions.)