I am going to make a prediction that you likely grew up in a smaller community in Utah or Eastern Idaho.

Wrong. I moved to Utah already an atheist. I didn't grow up in any one area, my family moved several times when I was younger. For example, I lived in Arizona, California, Georgia, and North Carolina before moving to Utah. The state I feel most confident in calling my home is California, since I lived there from 2004 to 2009.

In regards to the Journal of Discourse quote, the actual doctrine that Brigham Young is talking about it is very much emphasized and is found in the D&C, the Book of Abraham, and explicitly in the Temple. A dead giveaway is his reference to philosophers, he isn't talking about us being aliens but that our spirits always existed and come from where God is rather then being created at birth as thought in the rest of Christianity.

I highly disagree that this is what Brigham Young actually intended to teach. For example, in another part of the Journal of Discourses he says:

Though we have it in history that our father Adam was made of the dust of this earth, and that he knew nothing about his God previous to being made here, yet it is not so; and when we learn the truth we shall see and understand that he helped to make this world, and was the chief manager in that operation. He was the person who brought the animals and the seeds from other planets to this world, and brought a wife with him and stayed here. You may read and believe what you please as to what is found written in the Bible. Adam was made from the dust of an earth, but not from the dust of this earth. He was made as you and I are made, and no person was ever made upon any other principle. LINK

It does not seem at all that he is talking about the creation of their spirits, but the creation of their bodies.

Given this and your explanation of The God Delusion I take it you aren't that familiar with non-LDS Christian philosophy and the vast differences between us and them.

I have to admit I didn't regard myself as extremely familiar with Christian philosophy before my de-conversion, but I've learned a great deal since coming home from my mission. However, I don't think this was a very fair assessment of my knowledge on your part. There is nothing I've written that gives strong evidence for me being ignorant of Christian and Mormon theology. It seems to me you want to de-legitimize what I have to say by painting me as unintelligent and inexperienced with my own religion. Now, do you really think a person who has studied the Journal of Discourses wouldn't also most likely be a person who has spent a lot of time and energy investigating the rest of Mormon theology? I mean, a scholar I am not but I definitely know my way around Mormonism, more than most Mormons I know at the very least.

The church has not changed at all its position on same-sex marriage and just filed an amicus brief on the subject. I can see how your conclusion on the subject was drawn though.

There is a big difference between an "official position" and what is taught in the chapel and at the dinner table.