> it probably wasn't, but "nothing" is an overstatement.

No, "nothing" seems perfectly accurate to me. I don't see even a single indication in tone, phrasing or punctuation that is a classic LLM giveaway.

It's offensive to standards of decency to question the authenticity of someone's speech, and it doesn't matter if you phrase it as a question or preface it with "excuse me if not". Unless there is really a strong reason to suspect something, which is absolutely not the case here. It's offensive when it's not warranted.