Runwayedge:
Welcome to the process of making you a better pilot. YUP, YOU.
You are learning how NOT to be a captain! Congratulations.
The captain in question may have flown with some really bad copilots. I've seen it.
28 years ago I was with a turboprop regional, you would know the name. My first line trip (mind YOU I had been at two other little airlines and had plenty of time, the other two airlines went out of business) was with a crappy pilot.
His briefing was: I hate you new copilots so just sit on your hands and I'll fly, you can work the radio, try not to screw it up.
We were cleared into position and hold (that's what we called it back then, not LINE UP AND WAIT). Captain Wonderful advanced the throttles and started to roll for takeoff, I pulled the throttles back and said: WE ARE NOT CLEARED FOR TAKEOFF< HOLD POSITION>
A minuted later, the tower said: RADAR RELEASE DELAYED, REMAIN IN POSITION AND HOLD.
Captain wonderful looked at me, realizing I had saved his license. I explained to him that I had as many hours as he did and had worked at two other regionals and that I would like his cooperation.
He came around and treated me just fine after that. He apologized the next day after he saw that I could fly.
When you are in a plane you are obligated to keep things safe and you must help the captain do that. Put your ego aside.
ONCE YOU ARE ON THE GROUND tell him what you think (and I hope you are right). But it is time to "MAN UP" .
Good Luck