The linesman did nothing wrong. The Sharks and Knights game had a bunch of earlier altercations, some of them involving Kane, at that point in the third, he was on their radar and were told that enough was enough. The ref first grabs Englend and tries to escort him back into the play. He eventually grabs Kane and they lightly collide. It wasn't a push or tackle, as these social media idiots want to claim. The ref was gliding as he had a hold of Kane's jersey and Kane turned and stopped skating, resulting in the bump. Kane had been acting like an idiot all night long and it ended with another idiotic play.
Also to note, the current toughest guy in the league was in the lineup while the Sharks goaltender illegally checked the Knights' best player ( Stone ) and also saw Kane go after one of their non fighters.
