You're absolutely right that designers, regulators and, in some cases, courts should take every death (and accident/near miss) seriously. But it seems to me like there are two questions here. The first question is, "should we have self-driving cars?" and the second is "how can we make those cars as safe as possible?" When people say, "compare it to a human driver," they are suggesting a way to answer the first question, not the second. And that does not mean that they think the second question is "no big deal."

It's also worth noting that the quote he presented from the Oculus Rift thread was criticizing someone for pointing out that it is less concerning if surgical training equipment crashes than if surgical equipment crashes, not for saying that it is no big deal if someone dies in surgery. I didn't see anyone in that thread saying it would be ok for VR surgery equipment to fail.