Having defined that I was restricting the comments to Transhumanism as expressed on this site I saw no reason to continue restating the issue. Also, many, but not all, of the points brought up are not restricted to transhumanism as found on this site, as has been established with in this discussion, but to transhumanism in general.
The problem is that using one term to mean something closely related is bound to cause confusion even if you explicitly redefine it at the outset. I would really advise against doing that. And you weren't even entirely explicit about it; you wrote "Transhumanism, at least as expressed on this site, is as far as I can tell a religion" and then used "transhumanism" thereafter. It would have been clearer had you written something like "Transhumanism, at least as expressed on this site (which hereafter I will just refer to as transhumanism)", but even then I would advise against it for the reason above. (Especially because people often join these discussions in the middle.)