whatever this killalot character's motivation, his is a mind that cannot be changed.
he literally goes through the 3 subsections to the quoted rule and interprets them each incorrectly.
The head, unfortunately, did become the principal point of contact. The evidence shows that in a split second, Barrons head lowers as his knees bend and he extends towards the puck. If he straightens his legs, or even simply doesn't continue to bend them and lower the height of his head, his chest is the principal point of contact.
There was absolutely no unnecessary upward extension. Was the play unnecessary in the context of the game state? Dubious argument. It's the NHL you don't stop playing.
Second, Barron indeed makes head contact unavoidable by leaning down. Slow mo makes it seem like there's an eon for Trouba to weigh his options, there's not.
The evidence is there. There's 2 dudes insisting against it.
Again: the head unfortunately was principal point of contact. But because that was due to Barron's movements, it changed what would have been a body contact hit. Legal.