Yes, if that different poster believed the same thing.

There is a whole army of people out there who have a serious problem with accepting reality and it is useful to point out that someone is arguing with someone else who does not accept reality as it is commonly experienced. That saves everybody time, just like we don't feed the trolls we also should not waste cycles on engaging people who refuse to accept evidence anyway. Think of it as a PSA rather than an ad-hominem attack, you are assuming that the argument was brought in good faith, I don't.