Blunderous refereeing. Yes the players were guilty of the cheating but the ref allowed that game to descend into chaos. 
 
I chuckled to myself when the Netherlands refused to give the ball back after Portugal kicked it out. It was terrible sportsmanship but I just had a feeling that the Dutch were going to do that, it was that kind of game, and smiled to myself when they proved me right.
I've never seen a match at this level where the ball wasn't returned from injury. 
It made Portugal go immediately mental. 
 
The players were more to blame than the ref.