This is partially true.. as someone who learned to drive in Alaska and have been using studded tires off and on for almost 30 years, I can say they help, but you have to keep them from spinning/locking up... drive correctly and they help a lot.
There was a PSA/commercial the Alaska State Troopers ran back in the 80's that had a little old lady shaking her finger at you saying "Feather your brakes, sonny!"
Of course this was before anti-lock brakes were so prevalent.
Studs don't help in deep snow, and they don't help if you spin the tires or lock up wheels... but if you drive properly they will get you across glare/black ice without starting to slide.
Oh, and true rednecks drive on bald tires, or monster truck tires if they have a job.