While arguing to the point of not being able to complete a flight hints at a smidgen of unprofessionalism, it's really impossible to draw any firm conclusions about anything without seeing a transcript of the conversation. It would certainly be interesting to see. Maybe one of the pilots had a legitimate concern, maybe they were both just stubborn … who knows? But removing them from the flight does seem prudent until things can be investigated—impossible to comment on the suspension without knowing exactly what happened in the cockpit.