"Perceived" attitude? Try demonstrated attitude.
When tasked about their lack of punctuation, their response was - quite simply - arrogant. No consideration was given that maybe, just maybe, there are some people in the world that might find a more conciliatory response more agreeable.
You can argue all you like, but you only get one chance to make a first impression.
The Moving Finger writes; and, having writ,
Moves on: nor all thy Piety nor Wit
Shall lure it back to cancel half a Line,
Nor all thy Tears wash out a Word of it.
That's my take - and I'll leave this thread with it.