Förstemann Squats

They are not rubbish. Thats how you squat when you are going heavy. Hitting your hamstrings on your calves would actually be a dangerous way to work with maximal weights and to some degree, cheating.

A parallel squat is when the crease of the hip is below the tip of the knee like this:

In power lifting competitions they often allow less.

If someone cannot squat an empty bar to full depth, then they suck at squatting. It shows that they lack the muscle control and proprioception. Even if someone is tight and inflexible, they should have the muscle control to be able to keep their backs tight and force themselves into a full squat.

I am intrigued to hear how a parrell or below squat is "cheating"? I do agree that those squats are not rubbish, I would offer though that he was probably just the wrong side of weight verses ego in this set, I have seen other videos where his form is better and he goes a little deeper.