I've read the course work and It says in a round about way NITROX doesn't make diving safer but i think the logic they are using is you can't make something safer that isn't unsafe.
The element in diving that creates the possibility of getting bent is to much nitrogen and Nitrox decreases the amount of nitrogen you get while diving.
It seems logical to me to say Nitrox makes diving safer. lets face it every once in a while someone gets bent. however the stats are you have a .04% chance of that happening to the average joediver.
Its marketed as a value of staying down longer and thats definitely true.