Not really in the grand scheme of things.
That tractor probably weighs 3 tonne at most, with over half of that on the back axle, but we'll say 50% split to give them the benefit.
It's still got a rotavator on the back acting as a counter balance.
Loader distance gives a good bit leverage.
So you're probably looking at 750kg force going through the bucket.
Over 4 stands, that's only 187.5kg on each stand, which given the base model stand is rated for 1100lb/500kg, is pretty poor.
If they'd maybe done the test with only 2 stands, it might be impressive, but as it stands, it's a stunt designed to look impressive to those who don't know any better.