That is a tricky test! You can idle the car, and it doesn't know that the wheel is slipping because all vehicles have to have some way for you to stop. So, he's technically at a stop, just idling. Notice as soon as he comes up off idle, the car moves forward, but he stops it right away to make it look like it failed.
I know the new Mazda system is good, but c'mon, that's clearly messed up.
Everyone derided the old "90:10" Subaru AWD system as found in the long-ago automatic equipped cars. Well, our old Forester has that so-called "weak" system and it kicks a$$.
The reality is that for 99.9% of people out there, even the slip/grip systems are more than enough AWD.