Reductionism and the LDS Faith

Reductionism is the idea that, simply put, all phenomena are comprised of simpler phenomena, down until only a few basic rules govern the whole thing.
This view supports the concept that human behavior is just psychology, which is just specialized biology, which is just specialized chemistry, which is just specialized physics, which is ultimately knowable through mathematical models only.  Thus, human beings and their behavior are nothing more than the interactions of many, many particles based on a few basic rules.

I tend to be reductionist in my thinking.  Religious folks, of course, tend to reject the idea of reductionism, because it demotes human beings to somewhat-less than "the image of god."
However, I have noticed a very peculiar aspect of Mormon theology (especially of liberal Mormons who tend to accept modern ideas of ethics and fairness).
Any person is accountable for his or her own actions, right?  The body, of course, is in under the control of the spirit, somewhere in which consciousness lurks.
However, when a person is a sociopath, or has a disability that affects his or her behavior, these things are clearly linked to certain aspects of the formation and operation of the specific brain in question.  The funny thing is, Mormons are totally accepting of this fact, as long as the behavior explained is outside the realm of what is desirable to Mormons.
"You're depressed?  Well, that's a trial you've been given, not your fault.  Your brain is broke!"
"He killed himself during a manic episode?  Well, it wasn't him.  It was his malfunctioning brain."

At the same time, anything good is a result of a person's conscious and deliberate decisions, which are made by the true essence of that person, the spirit.
"I am happy because I have chosen to live the gospel of Jesus Christ."
"I just know that the way I feel couldn't be coming from me, it's the spirit."

Would these people be offended if I were to suggest to them that maybe their reactions and feelings were the result of brain chemistry?  Would they be mortified that I thought that behaviors like kindness and a sense of justice are solely the result of millions of years of natural selection?  I suspect they would!

Then why is it okay for these people to tell me that my depression is a result of my brain chemistry?  It isn't part of the "real me."  It is part of the transient trials in the life that come with a my body, and will go away when I die.  Okay, great.  What about my desire to do good in the world?  Oh, well that's the real me!  I'm a good person because my spiritual essence is good, in spite of my body and brain chemistry!

This can be applied very broadly.  The most liberal of truly-believing Mormons will kindly try to tell Homosexuals that they are "broken."  They have this trial, but if they just wait, they'll find out that who they really are is not gay, but actually conforms perfectly to every Mormon ideal.

Mormons, therefore, seem to be selectively reductionist.  (and that's the nice ones...)  They are willing to ascribe things that are undesirable that people "can't help" to neurobiology, but not anything they experience which strengthens or confirms their own faith.

Ultimately, I prefer this view to condemnation without exception.  But it still seems to fall short of truly "open-minded," because it discourages introspection in all aspects of a person's behavior.  It is blasphemous and demeaning of god to suggest that anything good comes from somewhere other than him, but it is more blasphemous and demeaning of god to suggest that anything bad comes from him.  If you believe this, there is no actual way to scrutinize god or his involvement in the world.  It is automatic a priori acceptance of a complete worldview, with a clause built right in that these beliefs can never be disproved.