Just guessing. Maybe he had some resentment that you are flying a "12 first class pax, 64 coach pax airliner" for a fraction of the pay, and a job that should be at mainline?
At least the captain is compensated so he can pay the bills, but I can understand why any mainline pilot would have resentment towards any FO flying 70-90 pax around for crapbag wages. That's chipping away at his profession.
Not flamebait at all, but you don't think you're better in your 76 seat CRJ 900 with first class than if you were a 50 seat FO for the same rates do you? Sure hope not.