I am guessing they didn't compare cheap student violins against the Stradivarius, otherwise I am sure any reasonably competent violinist could tell immediately.
Modern construction method, including CNC machines can certainly make instruments a lot better than they did 'back in the day'. Check out Youtube for videos of the first guitars made at the Fender factory - those workers were freehand cutting the body shapes on a jig saw. No consistency at all. As much as a '56 Strat or a '59 Les Paul is in demand today, I bet there were a lot of dogs among the ones made back then.
I am sure there are thousands of violin makers today who can make a violin as good as a Strad. However, I've heard rumours that Stradivarius made his from wood that was thousands of years old that was extracted from a glacier - perhaps that is the special 'magic' that no one else can replicate?!?