While I agree some of the early arguments are a bit weak, I liked the author's discussion of the parallels to medical research---I think it gets across why some (including myself) think its worth approaching this exciting new technology with a slightly less cavalier attitude: In developing cancer drugs that could save millions of lives—just like robot cars are promised to do—we understand we can’t ignore problems in…
By Cavalier atitude you mean very slowly while thousands of people die every year.
Just because this technology MAY[1] save lives in the future doesn't mean you can sacrifice others for greater good.
This is also the reason why we don't allow for experimenting on humans in the medical field.
[1] This is something that while I am fan of Tesla I'm still convinced Google is doing this properly i.e. build autonomous system from the scratch. What Tesla offers is an autonomous system that is good enough to make driver confident about it and pay less attention (e.g. watching Harry Potter movie while driving), but not fool proof that it would prevent accidents that regular driver could easily avoid.