Northbeach
I think that what many people are trying to say is that if handling staff and/or aircrew have no better information to offer than "the delay is due to the late arrival of the incoming aircraft" (ie delayed because it's delayed), they should say either nothing or something like "We don't know the reason for the delay".
"...delay is due to late arrival of incoming aircraft" is an insult to passengers' intelligence; that's what winds people up so much.