In my opinion the following drivers are to blame:
Cecotto: outbraked himself and ended up with Leimer on top of him. Not clever, but it can happen – it’s not near as bad as the thing he did in Spain.
Ceccon: he was the one that rammed Bird ‘Schumacher style’ at the apex of Ste Devote, but it didn’t seem as if he had outbraked himself. In my opinion, what Ceccon did was much worse than what Cecotto did and I’m surprised no one seems to be picking up on this.
Leal: must have seen the Ceccon/Bird crash in front and the Cecotto crash to the left, but still he didn’t slow down enough, which forced him to run wide and take out Palmer to his left. Again, his action was worse than Cecotto’s imo.
Also, Haryanto stalled his car when he tried to pass the carnage, which I thought was pretty funny.