I agree mostly with what you've written in an effort to deflate digital-utopian hype, although I don't see much evidence that transhumanists are at all dangerous. The futurological drivel on io9 is essentially marketing material and not really deserving of analysis of any sort. Transhumanists make some scientific claims that seem to hold up to casual scrutiny and therefore the strongest arguments against transhumanism should be scientific arguments.Actually, I deny that transhumanists and other superlative futurologists make any claims that are sound scientifically, that are UNIQUE or ORIGINAL with them. That is to say, nobody ever needed to join a Robot Cult to affirm the things they say that are consonant with consensus science. (To be blunt, that even a Scientologist has figured out how to run a nice bath is not exactly surprising, but neither is this a good argument for Scientology.) What is wanted if one is trying to grasp superlative futurology or weigh its merits is to understand its actual content and contribution, surely?
While it is true that Robot Cultists believe all sorts of things that reasonable people do, one also notices that they also fervently believe in outcomes that are very marginal ones, which vary considerably from consensus expectations of actual experts and scientists who have devoted their lives to actual fields indispensable to the substance of claims and outcomes the belief in which is indeed UNIQUE and often ORIGINAL to the transhumanists.
How many actual biologists and gerontologists and medical professionals are signed up for cryonics after literally decades of cryonics hucksterism suffusing public discourse and popular discourse? How many practicing molecular biologists would bet their home mortgage on the expectation that swarms of reliably programmable robust room temperature self-replicating nanobots can cheaply manufacture superabundance of the Drexlerian kind any time soon after decades of high profile handwaving? How many actual network security experts or professional coders seeking to make software more user-friendly for actual companies are working on coding a "Friendly" Robot God? Sure there is a small cottage industry of pop-tech self-described futurists and guru wannabes who keep churning out their glossy re-treads on these themes for the rubes, but this has no life in the actual doing of science and research in the real world.
While we can all agree that sometimes, very rarely, bucking scientific consensus has put a dedicated researcher in a position to author a paradigm shift in our understanding of the world, the thing to notice about the Robot Cultists is:
[one] that they are attracted not to one, not to two, not to three, but often to dozens of marginal beliefs,
[two] that in each case it is easy to see the passion of their belief connects quite clearly to wish-fulfillment fantasies they often indulge openly (invulnerability! omniscience! immortality! superabundance! super powers!),
[three] that few to none of them have any stature in the fields they buck or are likely to achieve the stature to actually substantiate a paradigm shift.
Let me be clear, not only do superlative futurologists believe incidentally in some soundly scientific facts nobody has to join a Robot Cult to entertain seriously, but what superlative futurologists go on to do WITH at least some of those sound beliefs is to treat them as foundations mobilizing and validating a host of absolutely marginal beliefs all of which are indeed definitive of Robot Cultism.
What matters in my view are not their scientific and unscientific beliefs, but the discursive operations that are central to their mode of belief, for example the characteristic ways in which scientific beliefs serve unscientific ones in their rhetoric, characteristic argumentative gestures, tropes, conceits, figures, frames that both shape and connect their assertions over and over and over again. In other words, I believe that the most powerful critique of the transhumanists is a critique aimed at transhumanism, singularitarianism, techno-immortalism, nano-cornucopism, digital-utopianism as discourses and as a characteristic subcultures soliciting identification as such, that is to say with superlative futurology as a discursive or ideological or cultural phenomenon closely readable by rhetoricians and critical theorists and, of course, that is precisely where I lodge my own critique as a trained and professional rhetorician and critical theorist.
I happen to think squabbling with Robot Cultists over the scientific specifities is often a waste of time. Few futurologists are actually sufficiently trained in the scientific disciplines relevant to the outcomes they enthuse over enough to weigh the implausibility of their cherished outcomes on actually scientific terms. The problem of the inaccessibility of expert knowledges to outcomes of public concern is a much larger and quite urgent one, suffice it to say that this problem is exploited by Robot Cultists, both those fraudulently pretending to an expertise they do not earn and those in the futurological fandom who superficial grasp of some science is often worse than no grasp at all and who fancy that uncritical enthusiasm vouchsafes their faith in the utterances of futurological flim-flam artists.
To go down the rabbit hole with Robot Cultists debating "uploading" as immortal cyberangels in Holodeck Heaven or debating the Robot God Odds on actual consensus scientific or engineering terms is rarely the least bit productive. This is not because these techno-transcendentalists have any substance on their side but because an appearance of substance operates most essentially in their discourse to provide the pretext for faith. A debate with an actually knowledgeable scientist confounding their assumptions and aspirations will most likely function for them if anything as a ritual substantiating the scientific seriousness of their faithly utterances.
Make no mistake, the error in such a case is actually happening on the part of the SCIENTIST who has misrecognized the objective nature of the discursive/ subcultural phenomenon with which she is grappling.
In pretending a pseudo-scientific faith-based initiative in the service of techno-transcendent wish fulfillment fantasies can be adjudicated scientifically with the Robot Cultist, one concedes a scientific substance to their aspiration which is the only concession they ever really wanted or needed from you and from which they gain all they could ever get from such a transaction in any case. Conceding the existence of angels one is left only to debate angels on a pinhead as an outsider with a monk who has devoted his life to these games.