"Human drivers kill a lot of people" is true "AI will probably kill fewer people" is true but probably is doing a lot of work when you turn that into "no reason to slow down AI full speed ahead".

In fact that is exactly the point of the article, we shouldn't fall into the trap of not worrying about deaths for AI just because we have deaths from humans.

After all part of the problem with human deaths is we consider it normal. If we can avoid that trap with AI we can ensure we do better.