Seems to me you might also want to calm your F/O down a bit. He sounds a little too excitable.
Either way, report if you want, if you feel he's bringing your airline into disrepute. But don't confront him on the R/T. Don't ever wind people up when they're just about to go flying. And don't get yourself wound up, either. Not good for safety. Let it go and, if you have to, deal with it later, coolly and dispassionately.
OK, he might have misheard Ramp Control. But if he did, it's their problem and theirs to deal with, not yours. His aircraft is his to command - BY LAW. Let him command it. If the company (having received a report) don't like the way he's commanding his aircraft, it's their responsibility to deal with it.