"Further, at this moment at least, the genes that are being transferred artificially are in general not genes that would cause havoc if they somehow became mobi

"Further, at this moment at least, the genes that are being transferred artificially are in general not genes that would cause havoc if they somehow became mobilized from the species into which they were introduced" You are assuming that we have sufficient comprehension of these genes and their effects to make such claims definitively. And while we may have a very high degree of confidence in that, say enough confidence to entrust my life, your life, or hundreds of individual lives - entrusting the wellbeing of the entire planet requires a different scale of rigor. And that, I think, is the essence of Taleb's argument. 99.99% sure might be enough to get a drug approved, and it well should be, because only some fraction of the population is at risk. But because DNA is inherently self-propagating, a mistake can have extremely far-reaching consequences, and as such the tolerable level of risk must be orders of magnitude lower. This has been Taleb's essential, consistent thesis throughout his career. That humans are bad at assessing the probability of relatively unlikely events, and that when those events are extremely catastrophic, that cognitive deficiency can be disastrous.