There really has to be more to the story. The couple had to be doing more than dropping the f bomb in response to such a nasty remark. I may have responded with the exact same statement.
Or the old couple had been obnoxious on more than one occasion and/or they did more than just drop the f bomb.
Somewhere in the midst of everyone's story is the truth.
I would like to know what evidence the Captain used to make his decision to kick them off the ship.