Well, it MIGHT have something to do with airplanes being certified only in the Normal as opposed to the Utility category. (Intentional Spins being a big no-no in the former). Anyway, most primary trainers in common use won't do much more than a spiral dive anyway. A Cherokee, a 172 or a 150 will essentially auto recover if you pull the power and make some rudimentary efforts to get the nose up. There are exceptions, as I'm sure we'll soon hear.
(ok, I'll start: An attempted aileron roll in a Beechcraft Sport 180 at 11000 feet and about 90kias with a really low time student pilot who'd just seen Top Gun for the first time WILL result in a stall/spin requiring rudder to stop the rotation and fairly quick action to avoid VNE)
Fortunately, we were required to do spins as an earlier part of our 141 syllabus, thus, I just felt stupid rather than dead. Since that time, I've enjoyed avoiding unintentional spins, recovering from intentional ones (in appropriate aircraft) and thwarting attempts by evil simulator instructors to kill me during recurrent training for various twins.
Why would anyone NOT want to know how to get out of a spin?