The pilots were inexperienced. The right seat guy had less than 250 hours total time in any airplane. At that level of experience, he’s lucky to remember where the landing gear controls are. (He didn’t have 250 hours in the 737, but less than 250 hours in any airplane!) Even the captain had fewer hours than an average United first officer. At those low levels of experience, it’s just unrealistic to expect them to be that good with non-standard situations.