It is tempting to dismiss Koresh as a nut (which he certainly was). Atheists will use him as an example of how "religion poisons everything".
But this is a real life example of how theology matters, and we should take advantage to learn as much as we can (for many people paid a terrible price, we should not squander it).
The article doesn't address theology directly, but it is there to be teased out:
Page 2: "[believers are] resurrected so they can travel to a kingdom cut off to nonbelievers".
This is a fairly common (and mostly Biblical) belief. Mormons have a mult-level afterlife, where believers get the best and unbelievers get second best. Only the truly evil (in man's eyes) need to be relegated to Hell. It doesn't say what happens to nonbelievers, we would assume it is comparable to the Mormon idea.
Page 3, Doyle says "You don't have to believe as I do". This is interesting. First, what is the fate of unbelievers? If it is Hell, then you are doing a great disservice not to warn them. If not, I would assume the "believer's kingdom" is better than whatever nonbelievers get. Do you not want to share?
At the end of page 3 and into page 4 we are introduced to the horrors of this theology. It is interesting that things almost always devolve into either sex or money (and, for some reason, rarely both). That no one would stand up to him is sad. That Doyle would say "I couldn't argue because he'd show you where it was in the Bible" shows the importance of hermeneutics.
Page 4 also gives us this odd (singular) statement of Koresh's theology:
"There are three crucial points to understanding the Branch Davidian brand of religion.There's a lot of problems here, but I am trying to be concise.
First, God can appear in the flesh as a man. Second, that man doesn't have to be a good person. Third, if you question whether that man is God, then you are questioning God. In other words, the devil is responsible for your doubt."
The first point is taking the special and making it general (as people do with the gift of tongues). Just because it's in the Bible doesn't mean we should do it! Many of the stories there are instructional ("These people did X, then they were destroyed").
The second point is just wrong. In John 8:46, Jesus challenges the crowd to convict Him of sin - and there are no takers. That people could be deceived in this matter is a troubling point for rationalists, but all too common as a result of sin (here people may feel unwilling to speak up out of their own wrong fears).
The third point shows the danger of human authority, particularly the authority of an individual or small minority. Human authority must always be spread out (a local church needs many elders, with no one of them elevated above the others). Human authority must be challenged, and accepted only when supported with Biblical arguments. Tradition and history are excellent guides here - both for what is right, and for what will destroy us.