Yeah, rates are important, but also small sample size (and who's at fault matters - the companies claim that human drivers caused all 4).

So you're not wrong, but my point is that humans are awful drivers, prone to distraction and fatal crashes. (32,719 in 2013 alone). If anything else (terrorists, sharks, aliens) were causing 30k deaths a year, we'd wouldn't be blithely accepting it as the status quo and acting fearful of measures that could dramatically ameliorate the problem.