They always leave out a lot of factors: Are you given an option to kill the psycho who is trying to goad
you into killing? Are you given the option to kill yourself and thus deprive the psycho the satisfaction of seeing his experiment come to fruition? You can't just plunk a scenario in front of a person and tell them they only have limited options when reality is chaotic and you can choose to do a large number of things besides "nothing" and "bitch out and do what the psycho tells you to." And your options will depend largely on your individual circumstances.
There's also the problem that anyone psycho enough to put you into a position where you are forced to kill other people would not be trustworthy. How do you know the lever that switches the position of the trolley is correctly marked? The psycho might tell you that switching the trolley to the right routes the trolley to the track with one person on it, when it, in fact, might switch the trolley to the track with five people on it. The psycho might be honest about the working of the levers, but he could have placed an important scientist and/or philanthropist on the track with the one person on it, and 5 child molesters on the track with the 5 people on it. Who do you decide to save then?
When thinking about the Trolley Problem, I'm reminded of a scene I saw in the anime Gankutsuou. In the first episode, a pair of aristocratic teens are invited to dinner by a mysterious Count, who starts to get creepy and manipulative with one of the boys
who is the son of his most hated enemy. The Count then presents the boy with an interesting game to pass the time:
It's strongly indicated that this outcome was rigged by the Count from the start, and he was doing it specifically to cause distress to the boy and manipulate him. How much worse could you feel, than knowing you turned loose a murderer while trying to save an innocent man? Perhaps, when presented with a problem like this, the only winning move is not to play, but which of us would have the nerve to do nothing?
What distresses me about professors who push the "Do nothing; you won't be responsible" angle for the Trolley Problem is that it's all a lie. You are responsible for the things you choose NOT to do. But in some cases, doing nothing might be the best case scenario because (A.) you don't trust the person giving you the choice to be representing the scenario honestly, or (B.) you might think that doing
something might have a worse result than if you had chosen to do nothing. Whatever you do, you don't choose the Do Nothing option because it absolves you of any responsibility for the psycho's actions. As if THAT'S the most important outcome to ensure. "Oh sure, people died, but at least
I came away with a clear conscience." I suspect the reason these deranged academicians post the Trolley Problem to their students is the same reason why the Count played his "game" with the boy; to cause distress, and break down the psyche of impressionable children to make them easier to manipulate.