Transhumanism, when taken to its logical conclusion, would produce a population of human beings who would become accustomed to a subliminal programming of dehumanization.

Since it would be subliminal, this would easily pass for being "scientifically beneficial for humanity", and most people under such pretext would fail to see how it actually is taking the human out of humanness. It can help and has helped some people recover limbs and their agilities from them, and in this instance, transhuman imperative actually did something beneficial for a person needing prosthetics; of course, there is no denying this, that this would be a compelling "pro". However, ultimately, the aims and objectives for which Transhumanism represent are nefarious, deceptively so. Even most of its well-meaning advocates mistakenly presume that it will not degenerate human ability and competency; they would be wrong. First, it would be about helping patients recover limbs--then before you know it, a Transhumanist world-government is allowing one superminority of the world to subjugate the rest of the population under its rule by effectively stripping them of their very humanness under the guise of "this is for the greater good".

This is basically letting ungodly creatures not only play God, but letting them get away with it too.

There is a legitimate debate to be had. But it remains rightfully controversial.

Though I personally see more harm than good coming from Transhumanism gaining real power and mainstream support.