The crew meaning, if it makes part of the crew uncomfortable, and you could accomplish the task another way within the confines of the fom/fm, then you shouldn't do it.

I'm afraid it's an argument you wouldn't win as a first officer, inside or outside of the cockpit. Arguing against Captain's authority is a tough hill to climb. But go ahead and give it a shot. I'm sure it will work out for you...Scrappy.