It was not a fault, not here and not in japan either.
Watch the replay and you'll see he's BARELY touched on the shoulder. It's definitely not enough to make a player fall.
And if he was already leaning to fall because he was loosing balance then there's no reason to call the fault because he was falling alone.
That goal changed everything on the match, Brazil could not break Croatia's defense and in time Croatia was making some good comebacks from time to time, it was an open match. The goal swings the balance towards Brazil's side and forces Croatia to move on the offensive leaving their already tired defensive players spread out and without support.