Fred Warner has been fined $10,927 for Unnecessary Roughness, so clearly he wasn't an innocent party in this incident and he hasn't gotten away with it. Metcalf has been fined $19,123 for Unsportsmanlike Conduct, no surprise there. It's his 6th fine of the season and 7th fine in the calendar year.
later Edit: Deommodore Lenoir of the 49ers was also fined $5,617 for Unnecessary Roughness relating to the same incident. Smith-Njigba was fined $11,473 for Unnecessary Roughness for a separate incident later in the game.