It's more common sense. He shouldnt have done it and he knows he shouldn't have as there was a market running on an incident during a match he was involved in. Reality is to many its a bit of a stunt, and he didn't gain from it financially but had he not eaten a pie then there was no story and those punters would just have lost their bet (does that make sense?). The rules are so strict and any player above a certain level found betting on any football market has to answer as to why.As someone else has pointed out, the bet was set before the game, and seemingly not with him involved.
All of what you put applies, had he NOT eaten a pie. By your version, he's wrong whether he ate one or not. Looking at him, a choice of pie or no pie is a no brainer.