My biggest complaint about the horns is that people usually do it with the thumb perpendicular to the hand, sticking straight out sideways making an 'L' shape with the index finger. That is poor form. The thumb must be laid upon the middle and ring finger, and only upon the middle and ring finger.
That, and industrial music is not metal. If it was metal, it would be called metal, and not industrial. We don't make up genres for nothing here people.