MikeyMike01
U.S.S. Wang
That is not what determines if it's "manslaughter". What determines if it's manslaughter is:
1. There was an obvious risk of death that Petgrave ignored when doing his action.
2. Petgrave acted in a way that was far below any expected professional hockey player in his shoes.
Neither of these look true to me. I completely buy that Petgrave tried to stick out his leg to impede Johnson, but that alone doesn't take it to "manslaughter" risk. There is no reasonable way to argue that "sticking out your leg to impede a player" at all registers as a major risk of death for any normal hockey player, nor was it a play that no other hockey player would ever consider commiting.
Is it dirty? Sure, you can definitely argue that. But being a dirty hockey play doesn't take something to that criminal level.
If you believe the kick was intentional, which I do, then those two criteria are met.