All of these safety arguments can be legitimately applied to many things that are already legal. Anyone want to talk about guns? (just kidding. Don't make the moderator purge the conversation).
Seriously. We already have lethal versions of acceleration and speed. I doubt this will ever be legal, but I could definitely see it done with proper sensors and use. Sure, some idiot could kill someone with it, but wood chippers are still legal and they have been accidentally killing people forever.
Saying it can't be legal for safety reasons is a poor argument.