I have never, ever come across a Captain that has lied to the passengers to 'keep them quiet'. I've had times where we've been fed incorrect information by the people on the other end of the radio and we've relayed that only to find out it was incorrect but that is a very different thing to stating that crew would be complicit in lying to our passengers.
Sorry mate, but this guy either swallowed a whole bunch of smelly stuff, or you've just met your first!
And it's a little bit of a stretch to say no Captain has ever told porkys about why a flight is late!