Rationalization

Consider a thief. If you read in the news about someone who's stolen a car (say, from a poor senior on welfare), you probably feel disgust. But if you hear that he had mental illness or was regularly abused at home, you may feel sorry for him too. Most likely, you won't have as strong of a negative attitude toward him. Some courts may even loosen their convictions.
What do we say if asked why we don't hate the thief who is mentally ill, or a bully who is abused at home? They couldn't help it. They were a victim of society or consequence. It's the parents' fault. Et al.

But really, in effect, it is simply the case that we understand the source of their actions. It is the fact that there is a blaring, over-evident factor in determining their action. It makes understanding (or an illusion of understanding if you so wish to call it, it does not matter) them easy and unavoidable. And so, in these extreme cases where there is one clear factor that so strongly affects a person's actions, courts are willing to bend and people to sympathize.
However, the question is whether certain factors in affecting people's actions are "good" while others are "bad." (N.B. The factors could probably be called "reasons," but this is about the actual, ultimately physical, factors that determine what action a person will take, not the "reasons" they did it.)

As alluded to earlier, a common source of defenses and rationalizations is the matter of nature and nurture. All factors that affect how a person acts can be grouped into nature and nurture. A mental illness is an example of a really powerful factor due to a person's nature. Constant abuse by parents at home would be an example of nurture being an extremely influential factor. But since both of these can be justifications for someone's actions (in court, in our minds), it does not seem that the question of nurture versus nature is what makes a reason good or bad.
For further example, if someone is convinced or coerced into stealing someone else's wallet, you might defend said person's actions by saying it was the coercer's fault and not their own. Similarly, if a manic (assume they have bipolar disorder genetically) gets into a fight, many would forgive them, saying that clearly they cannot be held to account for their genetic deficiency.
So they are not responsible, it isn't their fault but the disease’s or the coercer’s.

Of course, it is usually only in these extreme cases that we consider these crimes okay in the sense that we say it’s not their fault. If the person had no genetic diseases and a good home life (and no other major sources for their action are in sight), how do they justify a crime? Why is it that they will be criticized by society, while a manic (who beat someone up because he was in his manic and aggressive stage of his mental illness) will not? As stated earlier, a seeming explanation of this is just the very fact that there are extreme factors. But this does not mean that it logically follows that they should or shouldn't be criticized (i.e. that they are good or bad).

Everything is determined by factors. Starting from the extreme case: no one will say that someone should be held to account for their own genetic mental illness. How about high testosterone levels? They didn't choose to have that. Clearly, they cannot be held responsible for that. Their parents abused them? They did not have control over that either. How about being greedy? They didn't choose that either. Or, did they? Here’s where people begin to blame. It's in their nature, but they can also change, can't they? And so we blame them for not changing (or at least we use the argument that they could have changed against those who say that they didn’t choose to be greedy). But, is this the right way to look at it? One must consider what affects how greedy people will be. Things like watching movies and television, being lectured/conditioned by parents, and the direct results of one's greed will affect whether or not one continues to be greedy or not (albeit one's intelligence and general nature will affect how this input is turned into change). Where does choice come into the equation? The clay being molded doesn't have choice. The flower growing doesn't have choice. The only possible distinction is that different clays will have different textures and whatnot, and will respond to input (nurture) differently. Whether or not you change your greediness, or your dishonesty, or whatever vice or sin, is determined by factors, not some magic force beyond this physical universe with a sign labeled "CHOICE." So, no, one cannot be held accountable for one’s own greed any more than for a mental illness. Society’s views on when immoral acts are defensible and when they aren’t are severely flawed. More importantly, our intuitions on what is okay and what is not okay are contradictory and hypocritical.

The old idea of turning society’s hatred on the criminals is outdated as well. The most vile and evil murderers and criminals of society and the most unscrupulous mass-murderers of history acted on the same human tendencies, whether of greed or anything else, that can be found in every single other human being in the world. When these tendencies are self-destructive, the instinct is to feel pity. When the tendencies turn on others, it is replaced with hatred. Yet those who hate the criminals have acted on the same tendencies before. For example, everyone has acted, at some point, on the malicious tendency of greed and stolen something that did not belong to them. Why, even in their hour of overcoming this tendency and turning to a "good" or "moral" life, will a human be willing to hate a fellow human who was not as able to escape?

"I think it's impossible to really understand somebody, what they want, what they believe, and not love them the way they love themselves."
-Orson Scott Card, Ender’s Game


Also, a small clarification should be made at this time. Stating something like "Luc broke the lamp because he was in a manic phase" is not a thorough description of the factors that affected his decision to break the lamp. Stating reasons/factors is generalizing the physical nature of our universe, of course, but one must also not be disillusioned into thinking stating a single reason/factor (even if it is, as in this case, a very major one) is even a superficially thorough description. It's not that we need list all the reasons/factors, just be aware that there are a near-infinite number of factors affecting pretty much any outcome.