ABCD Ethics Again

Re: My post of September 9, 2007 on ethics:
The one question that caused the most disagreement was the last one; it read: "My behavior is ethical when the effect of the behavior is more beneficial than harmful."
This was a bit ambiguous and perhaps the reason for the confusion. I should have said: My behavior is ethical when it benefits more people than it harms.
The explanation as to why the 5th statement is more false than true (...the burning of witches, for example, was in the interest of the majority as was slavery and discrimination against gay men and lesbians, certain religions, or different races)is even more appropriate to the rewritten statement.
Interestingly enough, the other night on Medium there was an application of this notion of ethics. Briefly, a teenager was persuaded by some malevolent character to force people to commit suicide. But, these were not just ordinary people; they were people who were going to commit horrendous crimes, e.g., killing everyone at a diner. The teen’s argument was that he was doing good work; after all, he was only killing one person to prevent that person from killing a whole group of people. When Allison protested, he told her to “do the math”—one life instead of 16. Of course, the information Allison receives in Medium is based on dreams which are often misleading. But, the argument was made very clear. If you could kill one person and in the process prevent the killing of several others, would you do it? Would that be ethical? If you find that behavior is ethical when it benefits more people than it harms,then you’d be forced to argue that killing an innocent person (and the person would be innocent at the time he or she is killed) would be ethical. Of course, we cannot predict with complete accuracy if this innocent person will really carry out the dastardly deed or not (and so the connection with Medium is certainly not perfect). And yet, we engage in pre-emptive wars, not very different from the situation depicted on Medium.