We not only think it is wrong; we think everyone should agree that it is wrong. This is not to say that something is wrong just because everyone agrees it is wrong. There is a logical possibility that we are mistaken and it is just our cultural conditioning that tells us these things are wrong. That would mean torturing people is not really wrong; we just think it is. .
We live in a retributionary society. The primary means of crime prevention is through what is called a "policy of deterrence". Basically, what this means is that by making the consequences for a crime very unpleasant, we hope to lower the amount of that crime. By electrocuting murderers, we hope to lower the number of murders. By jailing non-violent drug offenders, we hope to curb drug use. .
Our other primary source of guidance in these matters is religion. This is particularly true here in the United States where Christianity is almost, but not quite, the state religion. We are taught from a very young age that breaking the rules will result in our eternal damnation. Any number of acts could result in our suffering in the fiery pits of hell for eternity. In other words, religion has the same method of guiding our behavior as our laws. The similarity in approaches should not be surprising as our laws were originally based on the rules of the church. .
When someone is raised in a retributionary society, their moral area is tilted by fear, rather than being guided by the truth. When considering an action to do, or not to do, the question becomes, can I get away with it? What will happen if I get caught? How does the risk of failure measure against the benefits of success? Rarely do ethics enter into the equation. Should I do this? When the question of rightness has fully left the equation, we will have raised a completely ethically bankrupt generation. .
According to Aristotle, if you can teach a man why an act is wrong such that he believes in its wrongness, then he will act accordingly.