I don't find extreme over-caution to be too far-fetched at all. I often am frustrated that people ignore possible new technology and its possible positive consequences (i.e. in simple cases where there really isn't any negative in sight) but on the whole people are generally correct to be fearful of potentially negative unknowns.

Often this leads to extremely important safety measures. For example, you mention "self-driving cars and the possibility of an accident a human would have prevented" - but that is a very poor metric, as driving a vehicle is one of the most dangerous things you can possibly do with your time, and one of the most likely activities anyone does day to day to kill or injure yourself, another driver or passengers, a cyclist or pedestrian. It seems the end-game to this extreme over-caution will be a redesign of cities that, in fact, puts a final end to this: the bar is set for self-driving cars much higher than "necessary" (to reap benefits), but the end-game will be good.

For other examples of extreme over-caution: how many nuclear reactors have melted down in the United States? How many times does a Mars Rover just explode or stop receiving or answering communications, since a simple bash script was good enough? (And in that case, no lives are even at stake.) How many times do pacemakers have a blue screen of death? How often does a drug get taken off of the market since it turns out that if you take it, suddenly you'll keel over and die, oops.

I am very often frustrated by people ignoring benefits, but I simply don't object to the level of caution people place on these things.

I mean we are talking about engineering super-humans. Humans are the only biological organism that is currently not being genetically engineered for better characteristics. Do you want people to just splice in DNA willy-nilly, seeing if we can get smarter or faster or stronger babies, assuming they survive? Where does this end?

I am excited by the potential of technologies but by no means are people's skepticism less than justified! We have a fragile equilibrium with the environment and the technological environment we have created and caution, where there are very obvious negative potentialities, is not at all misplaced in my opinion!

This stuff is genuinely scary. One bad click and you engineer a psychopathic superhuman Hitler who does not share our morals but is able to manipulate, as a sociopath, all of our systems. This isn't "hypothetical" -- examples throughout history are real.

Genetic engineering of humans is very scary, in my opinion. The reason I do not have quite the same view of GMO is that a plant might very well be nothing more than the sum of its characteristics: its rate of growth in certain climates, its nutrient needs, how much protein, carbohydrates, fats it provides.

But a human is not just a set of characteristics, for the benefit of the rest of humans. Optimizing for these is very scary. Perhaps more than people are raising the alarm about.

You know how large supermarket fruit tastes bland and awful? (But it ships really well and is huge and looks great!).

Do you really want our humans to look like that in a few years? (with respect to some wrong metrics that were chosen to be optimized for.) These things are alarming. Really, they are. Really, really.