I dont agree with your take on the findings, but lets put that to one side.
The findings were that he knew about the plan to gain an advantage for driver Alonso by ordering driver Piquet crash.
The challenge (since this is the basis of finding): - the lack of access provided to prosecution documents and to the key witness;
He was responsible for all actions of the team (team principal implies this ancient looking type of personal responsibility).
Fair enough. But this did not even come into any of the deliberations.
His penalty would have seen mitigating circumstances if he had cooperated truthfully. He did not. Hence the big punishment.
Where is your proof (or the FIA's for that matter) that he did not cooperate truthfully? His involvement was never proved. The finding was actually that on balancce of probability, he knew.
I have twice listened to the proceeding in its entirety and the only word that came to mind was "Kangaroo". And yes, Max did assume the roles of complainant, investigator, prosecutor and judge.