Transhumanism as religion
I don't see how it's the same as dualism. Sure, a literal interpretation of the brain being a computer is problematic, but the principle is that if you simulate the material that makes up the brain perfectly, then that should function as a brain. In fact, it's denying that this is a possibility is what dualism posits - though whether it's a realistic possibility is different entirely, of course.
Except you left out the main reason why they want to simulate a brain: Immortality. I don't think it's out of the question that we could simulate a brain, the sticking point is whether your "uploaded" mind would be "you." And then we're off into the land of swamp men and p-zombies, let's not even go there.
Though I do contend that, just as "is there a meaning to life?" is loaded to whether you want a God or not, the "is it really you?" question is loaded to your fuzzy feelings over souls and whatnot.