Note: Anytime you see a post with one of the return groups as "alt.usenet.kooks" there's a pretty good chance t its trolling for votes. Yes, they actually have contests to see who can pull the most responses. In this case, followups are pointed at "alt.machines.cnc" so maybe they're just trying to trash that specific group.
In either case, if you must respond, strip the group list to just this group.