In all fairness, I thought there might be a little slap on the wrist coming, but at the same time the "off-topicness" was short-lived and very calm and respectful, so I'm not sure I really see the need to have deleted it as it's pretty much aleady been forgotten about and we moved very swiftly back to on-topic discussions.
Also, why couldn't some comments just have been edited rather than removed? I noticed some of my comments which had on-topic responses, and I'm guessing also had some off-topic ones too, have been completely erased.