I don't know if duck boats are "bad" as they are simply objects. However, there are many more people using automobiles in our society, and the utility of automobiles is much higher than duck boats (at least how we choose to employ them currently).

Also duck boats can be bad and so can car accidents. This is a non-sequitor.

I think the point was that they are uncharacteristically bad (not to belittle those killed in car accidents).