Because chiellini knows that it wasnt a big deal. He made a deal out of during the game because he obviously wanted Suarez to get his red card which he deserved. But that was it. There was nothing else in it. It didn't even draw any sort of blood. Mean while I've seen a goalkeeper kick a player in the face unprovoked and that was a normal thing which he just got a red and 3 games suspension. That kick to the face hospitalized the player and could have potentionally blinded the player in one eye. If you wana see it search "palacio kicked in the face by goalie".
This means he can't play for Liverpool until the 1st of November. He will also miss the first 3 matches of the Champions League.
Serves him right.