To that I would say that the relationship between vehicle speeds and deaths is not linear. Lowering speeds (via infrastructure, not limits) in cities to 20mph / 30km/h would probably cut deaths by 80% without affecting average travel times much.

It is a great analogy though, in both cases the issue comes down to ease of access to deadly weapons capable of killing a lot of people in a short time period. I remain ever surprised that we think the average person is qualified to handle such weapons, despite overwhelming evidence to the contrary.