Can anyone explain goalie interference? This was ruled as incidental contact
According to the league, as of last year at least, there are two situations where a goal can be disallowed due to goaltender interference.
The first is when an attacking player prevents a goalie from being able to move freely within his crease. That's not applicable here because the goalie is not within his crease.
The second is when an attacking player
intentionally makes contact with the goalie. I don't think that applies to the goal in question, either. The attacking skater is doing a fly-by on the goalie, and is positioned to skate past him well to the inside at the moment when the goalie moves the puck. The goalie backs into the attacking skater's path at the last instant, and the attacking skater further attempts to avoid a collision (lifting his leg to step over the goalie's skate, and avoiding leaning into the goalie). I don't see any intent to cause a collision on the attacking skater's part.